Some people(like me) have a sensitive skin you can get a rash from a lot of things like high temp.,getting angry,some types of food like fish bananas peaches guava strawberry chocolate so try to reduce eating this food. But only for insurance you should see a doctor to examine this rash.
This rash needs looking at by a doctor, its hard to give information on a rash without seeing it, but all rashes need an evaluation and maybe a biopsy, for a proper diagnosis, so you can have the right treatment for the rash, to clear it up.
It sounds to me like (don't laugh) a yeast infection, yes both women and men can get this. It probably developed because of the antibiotics that you were taking. Are you Diabetic? just asking because Diabetics tend to get these infections very easily. It is very treatable, if that's what it is you need to get an antifungle cream by the doctor, for it to go away. Good luck
Welcome to the MedHelp forum!
It is difficult to diagnose a rash on net. This could be an eczema, dermatitis, sweat dermatitis, fungal infection, infection with stool, poor hygiene causing infection. If you have diabetes then this needs to be investigated as it can result in skin problems. After a course of antibiotics also it is possible to get both bacterial and fungal infection of skin. However it cannot be an allergic reaction to the antibiotic as that would be more general. Correct treatment will depend on diagnosis, for which you will need to consult a skin specialist.
Hope this helps. Please let me know if there is any thing else and do keep me posted. Take care!