hello there, painting my sons room tonight and as i was doing it i've noticed alot of lumps and bumps on his wall which really annoy the perfectionist in me, i've also noticed there is a line down a section of his wall which i assume is wall paper or lining paper or something. can i sand the lumps and bumps down or will that just totally wreck the wall cause it has paper on it? I'm sorry if this is a stupid question, i wanna say I'm a woman, but that's insulting to women who can do diy, I'm just bloody useless lol. many thanks in advance for your advice