I was prescribed magic mouthwash for sore throat. i took percocet due to other pain issues. is it still ok to take magic mouthwash several hrs later?

Yes: Various recipes of "magic mouth wash" exist, but I am not aware of any that contain Acetaminophen or narcotic medication, either of which would potentially interact with or put you at risk for overdosing on the ingredients in percocet, which contains Acetaminophen and oxycodone. No driving when taking percocet, however.

Yes: Magic mouthwash has in it's ingredients, a topical anesthetic to make the area numb, kaopectate to coat the area and Benadryl (diphenhydramine) to help reduce swelling, you are not swallowing it, just rinse and spit.