interior paint
 

I painted my room with a textured roller. It looks horrible. At most, the difference in thickness is 4-5 mm. How can i make it flat again? can a put a lot of primer on it and expect it to be flat?:confused:

Sounds like you might have to skim coat the walls with a drywall compound and sand them smooth. Latex paint doesn't sand very well on it's own, it wants to ball up and tear loose, makes an even bigger mess. The drywall compound will harden to a sandable finish. A very thin coat will do, sand, then prime and re-paint.