Is it okay to use Retin-A on a 5 month old scar that is still red caused by a chemical burn? (Photos)

5 months ago i did something stupid. I picked a cystic pimple and then applying BP for 10 seconds (then washed it of). My dermatologist was very optimistic about the scar that it will even out eventually and the color will come back. Its still a bit atrophic and red after 5 months. Today I visited him and was concerned about the fact that on the scar are tiny little bumbs (very small pimples that are hard) and suggested to use Retin A every night on it. Is it safe? Or will cause more scarring??