Strange painless bumps on chin. I was suspecting that it may be perioral dermatitis although, it may just be acne bumps. (photo)

I'm an 18 year old female and nearly two months ago, these bumps appeared on my chin. However the bumps seemed to have multiplied and now they're a cluster of dry, slightly red spots. They don't burn, itch or seem to have fluid in them. I was using a gel similar to ziana however, rather than putting a thin layer over my whole face I would put a fairly thick layer over the initial spots. Could the bumps therefore be a reaction to using too much of the tretinoin/clindamycin gel or possibly POD?

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