I have seen many threads on these forums of people who have been bitten by a tick and developed a rash. If you develop any kind of rash after being bitten by a tick, or flu-like symptoms, pains etc.. You need antibiotic treatment immediatetly. Many, many people get bitten, get a rash and don't take any antibiotics; then many years later (i know someone who got bitten 15 years before he developed symptoms) have serious health problems. Don't wait untill you are ill, if you have a rash, you probably have lyme disease or co-infections. I have had chronic lyme disease for 4 years after being bitten, it took 14 months for any symptoms to occur, and I didn't even have a rash!
Just thought I would make this clear, if you have any worries after being bitten, go to your doctor a.S.A.P.