It's very possible that the tick's head is still stuck. You really shouldn't remove a tick using your fingers: the best way to do it is to use a specialist removing tool thingy. Just bear that in mind for the future, though. I really do suggest you go see a doctor. They should be able to get the head out for you and also inform you about the risk of Lyme Disease.
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ser·en·dip·i·ty (n)
the faculty or phenomenon
of finding valuable or agreeable things not sought for