Brief Answer: Fixed drug eruption/herpes progenitalis Detailed Answer: Hello dear, Welcome to healthcaremagic. I have read your query and understood your concern. I have seen the attached pics also. I could appreciate a lesion which seems to be fluid filled. It can be any of the following: 1) Fixed drug eruption: it is characterised by rash which appear within 1-4 weeks of taking any medication, with genitalia as a very common site of involvement. You have mentioned in history that you got cold a week ago. So, i will like to know whether you took some antibiotics or other related medication for that? 2) Herpes progenitalis: usually characterised by fluid filled lesions associated with burning sensation but at times may be asymptomatic. I will like to know the duration of the lesions? Kindly reply to my questions so that a possible diagnosis can be made and accordingly i will be able to advice you further. Stay healthy.