Does getting lightly hit on the top of the head with something sharp do any damage? and is brain damage possible by getting hit from something sharp without it penetrating the skull?

Which is it ? A light hit or near penetrating the skull ? The brain is covered by a thick skull and several membranes that mimic bubble wrap. Any hit that does not cause loss of consciousness or memory is unlikely to do damage.

Agree with Dr. Ferguson. If there is wound on your head, apply triple antibiotic cream to prevent infection. Have a healthy diet, exercise 30 minutes/day, drink plenty of water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. For nutrition: http://www.choosemyplate.gov/. Get HPV and Covid vaccines. Wish you good health!