How is Victor portrayed in the first chapter of Volume 2 in Mary Shelley's Frankenstein?

I have a different answer.  A the beginning of the first chapter in volume 2, Victor is located at his family home of Belrive. This is coincidentally the same place in which he witnessed the first effect of lightning during a thunderstorm. The family had retired to that home for a while in order to go through the grief and loss process after the deaths of Justine and William.

It was a bittersweet thing for Victor. He felt that he was finally free for once from the shadow of the monster, but that was not so. In fact, every time he realized what he had done he would feel even worse, especially now that he was isolated with his family. He himself admits to gnashing his teeth and wanting to commit suicide while in there. The guilt could not leave his mind, and he was deeply anxious throughout the whole time there.  

How is Victor portrayed in the first chapter of Volume 2 in Mary Shelley's Frankenstein?

At the end of Chapter Six, Volume One, of Mary Shelley's Frankenstein, Victor has finally returned to the man he was before he began his studies at the university in Ingolstadt—before he created the creature in his laboratory. He is filled with laughter and joy.

However, in the first chapter of Volume Two, Victor receives a letter from his father in Geneva. It informs Victor of the murder of his youngest brother, William, and Elizabeth's desolation at this loss. Victor is filled with despair over this loss of his beautiful and loving sibling. In his agony, he wants nothing more than to return home to be with his family.

However, before Victor reaches Geneva, waylaid by the closing of the town's gates at sundown, he comes upon a vision that makes all things clear to him regarding William's death. In the midst of a raging thunderstorm, between flashes of lightning, Victor sees the image of the monster he created walking on the landscape before him. For only a moment he wonders at the creature's presence. In the next instant, Victor is certain that it is the monster that has killed his brother. The anguish of this knowledge is compounded only by the realization that Victor is responsible for unleashing this villain upon the world, who has now taken his brother's young life.

Alas! I had turned loose into the world a depraved wretch, whose delight was in carnage and misery; had he not murdered by brother?...I considered the being whom I had cast among mankind, and endowed with the will and power to effect purposes of horror, such as the deed which he had now done, nearly in the light of my own vampire, my own spirit let loose from the grave, and forced to destroy all that was dear to me.

What is Victor's appearance in Mary Shelley's Frankenstein?

Victor Frankenstein himself is not afforded nearly as much physical description as his creature. Most of the narrative is told through Victor's first-person perspective, and his opportunities to describe his own appearance are limited; however, readers do get a glimpse at Frankenstein's physique through Walton's descriptions of him.

Walton relates the following in regard to Victor's appearance: "He was not, as the other traveller [the Creature] seemed to be, a savage inhabitant of some undiscovered island, but an European" (meaning that he is white, and thus, in Walton's eyes, respectable); his body is "dreadfully emaciated by fatigue and suffering"; and he has an expressive face, which is home to eyes that "have generally an expression of wildness, and even madness" but is also capable of lighting up "with a beam of benevolence and sweetness that I never saw equalled" when someone is kind to him. Walton takes kindly to Frankenstein, remarking that "He must have been a noble creature in his better days, being even now in wreck so attractive and amiable."

As Walton's letters continue, he becomes even more enthralled by Frankenstein and continues to emphasize his expressive face, which betrays the depths of Frankenstein's soul and feelings. Walton's description of Frankenstein ties the gravity of Frankenstein's story to his physical features themselves. Before the book shifts to Frankenstein's perspective, Walton offers this final description of how he looked while telling the tale:

Even now, as I commence my task, his full-toned voice swells in my ears; his lustrous eyes dwell on me with all their melancholy sweetness; I see his thin hand raised in animation, while the lineaments of his face are irradiated by the soul within.

Such an emphasis on physical features is in keeping with the nineteenth-century interest in physiognomy and phrenology, both pseudosciences that attempted to derive information about a person's disposition and intelligence based on their physical characteristics. Mary Shelley would have been aware of these ideas, and, like other European writers of the time period, she wrote her characters' physical descriptions to express some corresponding truth about their internal makeup.

After Walton's letters, readers do not get much further description of what Frankenstein looks like. But we do see him taking ill quite frequently, as he devotes all hours to his work and often neglects to eat or drink. It seems safe to imagine that, during the events of his story, he consistently appeared studious and a bit sickly (though he probably looked a bit healthier than he does by the time he meets Walton, when he has been well and truly worn ragged by his experience with the Creature).