
If the lump is big enough to be noticeable, do keep a close eye on it. I had that with one of my bitches and it turned out that the tick which had bitten her, although completely removed, had given her some kind of infection, which took ages to sort out. It would swell, and a course of antibiotics would follow, the swelling would go down then it would flare up again. In the end she needed surgery to remove infected tissue, which left her with a large scar down her neck.