Talk to Dermatologist on Chest Acne Small Red Bumps

Assalamualaikum doctor, I'm asking this for my sister she is suffering from chest acne from month of April , suddenly it starts happening even she never face this before , so we thought it's a reaction of heatwave or sweating due to weather condition in summer .we have tried so many home remedies but it doesn't work.then they appear after 5 to 10 days again in a month and also leave mark on skin she has very clean neck area before this acne . Kindly suggest any ointment for the treatment also tell me in how many days acne will be disappear.jazakAllah.