[Acne] any experience with doxy treatment?

So I’ve had acne pretty consistently for my entire life but never did anything about it until now. I was prescribed doxycycline and was told to use differin and a benzoyl peroxide cleanser. I got through the entire bottle of Doxy, which was I think a months worth. It all worked really well and my skin was great. That was at least a few months ago and my acting has started to pop back up. My dermatologist didn’t really give me any direction besides what I’ve already said and I don’t care to go back if I don’t have to. I’m thinking of refilling the prescription.. But should I expect to be on this forever in that case—If the effects only last for a few months?? I’ve heard mixed reviews about how it can work— some just take one round of it and never take it again vs sort of cycling it for years.

I know I can speak to my doctor about it, but I’m mostly wondering what others have experienced.