Are there any cures for impotence in islam? Ive masturbated so much that i have the side affetcs of masturbation such as low semen etc.. Now there is probability that im going to get married with sister inshallah but im afraid that i will not be able to satisfy her and due to impotence that i think i have. Ive stop masturbating and pure for almost 3weeks now alhamdulillah. Any tips of how to overcome my situation will be appreciated

All praise be to Allah, and may His peace and blessings be on the greatest messenger, Muhammad.
It is unclear whether or not you have impotence. Impotence (Erectile Dysfunction) means that your male organ does not become erect.
If you do have this condition, then it is a valid cause for her to request the annulment of marriage if it already took place. This is a condition that will cause the wife significant loss of rights. I would advise you to get treated first before you marry if you are truly impotent. That would mean a visit to a clinic that specializes in the treatment of sexual disorders.
Ask your lord Allah to cure you and rely on him while seeking such treatment.
Allah knows best.