The Last Judgement was completed much later (1538-41) than the rest of the Sistine Chapel ceiling (1508-12). As such, there are several stylistic changes in the work.
In the Last Judgement, several saints can be seen with identifying objects. St Bartholomew, who was flayed alive, can be seen carrying his own skin. The face on this skin is thought to be Michelangelo's self-portrait. (see image)
The only other known self-portrait of the artist appears on the Crucifixion of St Peter. Discovered during a modern restoration (2004-2009) - Michelangelo is shown as a horseman wearing a blue turban. It was originally thought that an orange-capped, cross-armed man in the painting may be representative of the artist, but these claims are now unpopular (compared to the horseman theory). In particular, the blue turban is reminiscent of the hats that painters worn by contemporary sculptors.