You can peroxide it after initally removing it, then treat with neosporin to help heal the boo boo, just make sure the cat doesn't lick that area. Depending on the type of tick, or how common lymes disease is in your area (It is pretty high risk here) you may want to watch out for signs of lymes.
Lyme Disease in Cats
I'm not a vet, but I am a vet tech student so I hope this helps!