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I have this problem too. Most of my face is fine but get spots really badly on my chin/jawline. It's worse as I'm breastfeeding so can't take anything medicine wise. I take evening primrose oil, and ground flaxseed mixed with yogurt as it's meant to help balance hormones. Have also been advised to try yoga or other exercise regularly, and try to avoid stress as it can produce cortisol which makes it worse.
Sorry, that's probably not a lot of help - if anyone else knows any magic solutions I'd love to hear them!
Hormonal problems like these can be caused by a condition called polycystic ovaries. A blood test can be done to see what your hormone levels are like. Tea tree oil can be good to use but you need to determine the actual cause rather than just treat the symptoms.