I have very fair skin and recently spent some time outdoors while painting my deck. I wore no sunscreen since I was only in the sun for a few short early morning hours. However, I did get a sight sunburn on my shoulders and upper arms. Now, I have a rash on my shoulders and upper arms....raised to the touch, red, itching and burning, stinging...painful at times......what could this be....what kind of cream/treatment do you recommend? Thanks.