Mojo had a big tick on his leg in the Fall.....It was weird...a big circle that was swollen around the edges, but indented in the center. I put peroixe and neosporin on it and took him to the vet to have it checked. She said the neosporin wouldn't do any good because if there was a problem, it would be under his skin.....she said it looked okay, like the head was out....and I was pretty sure I had gotten the head out.....and thankfully, we didn't have to go back. It started to go down and he never acted sick or anything! WHEW!
But, I never hurts to have it checked....I always feel better...even though a lot of times, I pay for just that calming of my own nerves...not a medical problem! HA!
I was also told at one time...that a lot of times it is the bacteria that gets squeezed back into the body (of the animal/person) from the tick when you pull it off that can cause the sore, sickness, etc.