There are many reasons for acne on the edge of the chin and neck, mainly for the following reasons: first, caused by endocrine disorders, adolescent boys and girls hormone secretion level disorder, the skin will appear acne, you need to go to the hospital to check the level of androgen, estrogen, progesterone secretion, if there is an abnormality symptomatic treatment can be. The second, unbalanced oil secretion caused by the face and neck daily exposure to dust, not timely cleaning of the skin leading to local pore blockage, skin residual substances can not be discharged to form acne. The third, and fungal infection related, Malassezia folliculitis infection of the skin after the chin, neck and back will appear inflammatory red bumps, it is recommended to do fungal immunofluorescence examination at the hospital, microscopic can see the spores infection, antifungal treatment can be.