(All my threads seem to be about cats now)

Anyway, my kitten is limping on one of its backlegs, it cries when it tries to walk and i'm not sure what to do. It kills me when he cries :(
Should i see a vet, or will it just heal?

And my kitten seems to be getting fleas, i noticied one today, and one on it yesterday. What are the best treatments for a 8 week old kitten?