hi..Thanks for your query
I would like to mention here that Acne
can present in several forms. This includes whiteheads, blackheads, and red, inflammed patches of skin (such as cysts).In the course of evolution, you may have any or all of these.Sometimes ,over a period of time, even if you are under a specific for of therapy,one agent might not be enough to handle it completely.This is based on the various internal hormonal
stimuli as well, which can change several times in a month or year.
Although you have been compliant with the methods advised to you, I feel that only this agent in the lowest dose might not suffice now.there may be a need of addition in oral /topical therapies.U have not mentioned your age now.Tretiva is a medicine which has potential side effects if used continuously,hence it is good to use the other agent now.
You can do a few sittings of Salicylic acid
peels with qualified dermatologist
to attain more sustained results without the potential side- effects of Retinoid
Hope this helps..take care
U definitely do not need to stop anything now, however please visits the doctor early so that there are no delays in the onset of more efficacious therapies.