I was bitten by a tick in may 2008 in tennessee with a resulting bullseye rash; at this point in time, how can i tell whether i have lyme or stari?

No need: The likelihood because you actually saw/felt the tick bite, as well as location, suggests that you had stari rather than lyme; treatment is with doxycycline, regardless, because of the risk that it could be lyme disease. Since it is still unknown what causes stari (the actual pathogen, not the tick), it is unknown whether antibiotics truly help. Patients with stari recover on them, though.