we had a boy that bounced a basketball off his lips for self stim- at school we tried to distract but by the time we got him back after weekends or especially after long vacations he would have done it so much as home, his face would be red and badly chafed.
We tried to get mom to substitute with balloons if she had to let him do it- and it helped a lot.... so maybe if he is going to do it no matter what- try something "lighter"