What causes bumps on the chest and what treatment options are there? (photo)

Thanks for the very helpful picture. Your condition is typical of moderate to severe acne, due to the presence of active pimples, acne scars and comedones (or blackheads). The dark coloured, bigger lumps that you described is an infected cyst – the reason why it’s tender, swollen and dark coloured, is because your body mounts an inflammatory response to the clogged pores and trapped bacteria; similar to how your other pimples are formed.

I noticed that I tend to breakouts after holidays. Yes, weather and humidity changes can sometimes trigger breakouts. Stress/poor quality of sleep due to jet lag and time differences can also contribute. Speaking from personal experience here; I tend to break out much worse in Singapore than I did living in the UK. Went to national skin centre for consultation, and was given some watery creams and Cetaphil products to use. Hard to comment on what you were given, but from what you’ve described here, NSC doesn’t seem to have given you anything specifically for acne treatment.