With my son and his similar 3-4 SPD friends, there is no skin reaction to creams or shampoos, etc. They just don't like being touched unless you warn them or ask permission; basically being surprised is a no-no.
If the skin reacts to things, you may want to look into a skin allergy/dermatitis. There is also urticaria - reactions to touch, water, sun, etc. Do a quick search on urticaria and you'll see skin reacts like mosquito bites/welts, plus more. I hope this helps.
MY 3 yr old son will put balls in his shirt and play. As soon as he realizes I am watching him he runs and hides. He is VERY persistent about me leaving