I have uveitis, is it okay to use my eyes if I have it?

Yes. The response to medication and the persistence of the condition is independent of whether or not you use your eyes. And of course you need to see to function even while uveitis is active.
Yes. Uveitis - an inflammation of the internal eye is not a reason not to use the eyes- but if uncontrolled light sensitivity and focusing may be difficult.
Yes. Using your eyes will not make your uveitis worse. Be sure that you are under treatment, however.