hope after minocycline?

I'm 16 years old and suffer from acne, i've already been on erythromycin and am currently on minocyline (minocin mr), which worked wonderfully at first but is now wearing off.

I've read that minocycline is the most effective Antibiotic and i'm now worried that since i seem to have become resistant to it, no other Antibiotics will be effective.

Can anyone who has been on minocycline, tell me what they then went onto once the effects had worn off, and whether it was effective. I'd be very appreciative of feedback.