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.
So I have many strange behaviors but I've usually assumed it was my social anxiety until I came across something on the internet about Sensory Defensive
I'm a teen who was diagnosed with level 1 autism at age 13. Since I was very young I had sensory issues, they were very noticeable when I was in preschool,