Boudicca’s rebellion really did not have much of an impact, certainly not in the way that she would probably have wanted it to be important.
Boudicca, presumably, wanted to maintain the independence of the Iceni from the Romans. She presumably also would have liked to drive the Romans completely out of England and restore it to Celtic rule. Neither of these things happened. Instead, her rebellion appears to have helped to consolidate Roman rule in Britain.
To be fair, Boudicca’s rebellion almost worked. The rebels sacked London. They likewise destroyed other large Roman towns. In the end, however, the Roman army crushed the rebellion.
In the long run, Boudicca’s rebellion seems to have consolidated Roman rule. After the rebellion, there was never another serious uprising. The Romans contributed to this by doing a better job of ruling the Celts. For example, they became more respectful of the Celtic religion and built temples for the Celtic gods. However, the Celts appear to have realized that the rebellion showed that they could not possibly defeat the Romans. Therefore, it led them to be more quiescent and accepting of Roman rule in the long run.