It is quite common in ur age.It is not a disease, it is a normal physiological phenomenon.
We have some hormonal changes during our adolescence.
If it occur very frequently then u can take medicine-
1)Acid Phos-200 -2 drops twice daily for 4 days
2)Kali phos 12X-4 tab twice daily for 3 weeks.
Next Steps
Consult a homoeopathic doctor online or offline and take proper information and knowledge about this problems and if necessary then he will also treat u.