I put sunscreen on my forehead and went in the pool now it hurts like a sunburn but its not burnt, its red itchy and has bumps.?

Skin irritant. It could be a reaction from the sunscreen and possibly any chemicals that were in the pool. It doesn't sound like a sunburn. Did you place the sunscreen anywhere else on your body, and did you get a rash? Best thing to do is just leave it alone. You can try some of the otc itch cream, some cool packs if it's really itchy. If no improvement in a few days, you should see your doc!