Is it possible that sudden changes in temperature ( from 12C to 37C ) can affect menstruation? I lost my periods after we went in holiday last April to a tropical country.

Is it any treatment for adult acne?

Hi. Spots on the back is acne too. Acne can affect the face, neck, chest, or back.
Maybe you outgrown it, but it's still work to know that UV rays (as in sunshine ) helps a lot.
UV are disinfecting and healing. That's why people acne improve after the summer holidays.