If you think you have been bitten, if you have been bitten, if you don't know you've been bitten but have the bullseye rash then it's time to go to the doctors.
You'll need to be put on a 3 weeks minimum supply of antibiotics.
If you're still concerened after the 3 weeks course is up then go back to the doctors and insist on another 3 weeks course. We're all different. Sometimes the first course will kill the bacteria, but not always.