I just finished prevpac (lansoprazole amoxicillin and clarithromycin) with almost no side effects .can i get them later?

Probably not: Usually the side effects you would get with the medications in a prevpac (lansoprazole amoxicillin and clarithromycin) would occur within a few days of starting the medications. If you have taken the whole prevpac (lansoprazole amoxicillin and clarithromycin) and have not had any side effects you should be fine.

Unlikely: You are almost certainly in the clear. There are some people who get a late rash with amoxicillin.