L.L.
Sounds like he is very interested in hair and its texture. Maybe you could get him a doll with hair for him to explore or a horse with hair for its mane. Take a look around a good toy store and you are sure to find something. Maybe he could take his new toy to play group or maybe after a few days thoroughly exploring the hair he will be done with this phase. Use the toy to show him gentle ways to explore the hair. Or suggest that they make hats at play group so everyone's head is covered.