What happens if I have eardrum popped and had an infection after that?

Rupture? By popped do you mean rupture. An acute infection can cause the eardrum to rupture. This can be painful and is followed by drainage of the pus from the ear, which can then decrease the pain as the pressure is released. Happily, most of these heal on their own. If it doesn't, then you may need surgery to repair the hole.