Hi Anna, I would recommend you to see the skin specialist, some have free consultation, so they can analyse your skin closely. I am based in Soham (in Cambridgeshire). Some acne might require medical treatments. There are many factors can be involved, such as hormones, diet, life style in general, skincare routine, and etc. If this condition is developing recently, then the cause of it should be addressed. Acne around chin area could be caused due to hormonal changes. Please visit the following link the article about the Acne:
http://tarabeauty.org.uk/Acne.html