Can comedones come back after Tretinoin treatment?

I started topical Tretionoin 0.025% 4 weeks ago. At first I started 3x a week, then 2x. I went through the purging stage and by the 3rd week, I've been using it every night already, and almost 95% of my comedones are gone. But now at the 4th week mark, they're starting to come back. They're tiny but definity plenty. Possibly an extra 40% came back. Is this possible and what should I do?