Hard to tell without seeing them. Are the arm and back areas exposed to the
sunActinic keratosis
Fontanelles - sunken
Liver spots
Sun protection
Sunburn
Sunburn first aid
Sunken fontanelles (superior view)? If so, try using a broad-specturm UVA/UVB sunscreen. If that fails, try an antihistamine (chlortrimeton--over the counter-- one hour before exposure. If those fail, you may have to cover up when you go outside, not necessarily such a bad idea anyway.
Best.
Dr. Rockoff