Your self inflicted wounds seem to have got secondarily infected. Not only they require proper cleaning and dressing but also a proper course of systemic and topical antibiotics. You are too young to deal with it on your own, kindly let your guardian know so that you can be accompanied to a proper medical centre. Secondly, you need counselling
for self inflicted harm. Don't be scared or ashamed to let your parents know as no one but your parents would support you through thick and thin. Take care.