Have tick bite that looks like a pimple on back of head 5yr old?

Did you remove the t: Did you remove the tick? Was it a deer tick-----a tiny one? Was it deeply embedded? Engorged with blood? If it was not a deer tick, if not embedded yet, if not feeding yet, then nothing to do except be aware of possible tick-born illness during next 3 weeks. Contact your DR if you had to dig it out. Often it is prudent to give a single dose of antibiotic within 2 days.