I understand that this is scary for you but I seriously doubt that you infected your son with HSV 1. You are correct, the skin of his little head is quite thick and I think this presents a very low risk situation.
I would suggest that for the next week or so, you just keep a very normal eye on him, be sure he’s eating well and seeming normal. If you have any concerns, check in with your pediatrician, but I’m guessing he will be absolutely fine.
Is this your first baby?