Hello, I was on doxycycline 50mg for about 3 months and it was working well. Then I got bumped up to 100mg and it gave me awful stomah aches. So, now Im taking minocyxline 100mg. During the week or two I was taking no antibiotic my acne has flared up a lot. Will minocycline be as effective as the doxycycline? Is there really a big difference between the two? And how long will it take to start working?