The last feral kitten I brought home had one, it had already emerged by the time we got her to the vet, and it left an awful infected sore in her neck. Lots of antibiotics, pain meds and twice daily clean out of the spot. The sooner you get to the vet the better.
Jennie, Gary & our kids:
cat colony: Hunter S Tomcat, Archie and Mehitable, Witch, and Calamity Jane, Cuddlebug, Havana, Ghost, Spitfire Liz, Little Bit, Jesse, Moe, Cali, Stardust, Anastasia & Christy, Sally and the 5 boys
dog pack Heinz and Heidi
rip Tiger, Rabbit, Two Stars, Angel,Elaine, Mungo Jerry, Tex and Ijimus. I'll meet y'all at the bridge.