You didn't give us much information. The only way to try and mend things is through communication. If they are cool towards you then try to meet with them to find out what the problem is (if you don't know) and if you did something wrong to offend or hurt this person then remind them you are only human and make mistakes, but you'll learn from this mistake and try harder because you love them. MEAN IT! Communications comes before sex for a successful relationship. Silence is not always golden!