"i had severe acne on my face, chest and back. my dermatologist prescribed me doxycycline and at first the medicine seemed hopeless, but with time (approximately 8 weeks) i started to see results on my face. within 3 months my face was completely clear. unfortunately, my face was clear for only 2 months and i began to have cystic acne again. i&#039;m switching to bactrim because doxycycline has stopped working and the glory was short lived."