How can I stop this crazy itching on my arms, neck, and face?

I just got out of the shower and I was feeling itchy when I got out. I didn't use anything new except scrubbed my neck with a washcloth because I got some paint on it earlier. Not I'm itching and it burns after a while if I don't itch it. It's mostly on my arms and neck but I can feel it spreading. A cold pack helps it a bit and I took some benadryl so I'm waiting for that to kick in. My nails are too short to scratch well so I'm rubbing my skin and applying a cold pack like crazy. Please! How can I stop itching!