Thank you for the question.
While oral doxycycline is an effective treatment for acne and cystic acne, there are various reasons why it may have stopped working. You may have developed antibiotic resistance to the doxycycline and this makes the treatment less effective.
Other reasons may be the dose of the medication and you have to ensure that the medication is taken at the optimal dose.
Sometimes, people do fail oral doxycycline treatment. While it is effective for most cases of acne and cystic acne, there are individuals who fail to respond to the treatment. In this case, switching to other treatments will be needed.
You should discuss this further with your attending doctor or dermatologist.
