I do remember my dermatologist telling me that acne in the chin area is typically hormonal, but it also could be a couple of other things. Your toothpaste can cause acne around your mouth/chin. Does it have sodium laureth sulfate in it? If so, try one without SLS for a while and see if that helps. If you use an oily lip balm at night that could be breaking you out too. It could also be the foods you're eating. Try eating less oily foods, less junk, and less dairy to see if that helps as well. Is it the sides of your chin? Try changing your pillowcase every other night.

If you do believe it's hormonal, birth control or spironolactone can help. Birth control helps regulate your hormones. There are both "bad" and "good" birth control pills for acne, so you might look into that or discuss it with your dermatologist/GP/gyno before starting. Spironolactone is antiandrogen. They can be taken together or separate. But these are medications, and you should take that into careful consideration before starting either.