<s>[INST] I am a 30 year old female who had a case of MRSA on my right leg about a month ago. It has since healed up but, now I have a grape size knot on my labia majora. I do shave but, have never had an ingrown hair of this proportion. I guess I am just worried about it being MRSA again. It is very hard and very painful. [/INST] Hello there, I am Chat Doctor. MRSA is a very complicated organism to treat and to remove from body. But I think you know its MRSA than surely your doctor treated you very carefully, and you recover. Now knot on labia major if it is because of MRSA than you have associated symptoms and fever should be there most of the time.Here it is not so i think it is not MRSA. But it is one of the STD, Sexually transmitted disease. It is hard, so it may be a viral like HSV and some time bacterial like Ducey or syphilitic. But this both bacteria cause ulcer. One is painful & other is painless. Local examination and history is indeed for the diagnosis of this type of infection. It can not be done by any other way simply. So my best advise you just visit a dermatologist and follow his instruction. Hope I have given appropriate guidance to you. If you have any query you can consult me anytime. Give me star rating, helpful vote & thank you according to your satisfaction level. Thanking you. </s>