Whats Wrong With My cat??

my cat/kitten in 10 months. shes a indoor cat but has been outside but not since september. she has been givin flea bathes in october bc she had scabs and they went away but tonight i went to go scrtach her in her favorite place on her neck and theres a bump and its red n a scab. i lookd for a tick but didnt see one. what is it?? what can ido to help it?? it just appered today.