Thank you for the additional information and picture.
Well there are a couple of things which seem likely here, from the picture which you attached it seems like that the swelling and irritation has subsided quite a bit. Although vinegar is not recommended unless it is a yeast infection but it seems to have worked in your case. It looks like that you had an allergic reaction to something, it could be from the condom (if you used one) or any lubricating gel (if used). But it is more likely to be local irritation or an allergic reaction rather than anything else. Now if this is the case you can use OTc antihistamines if the swelling returns or a single dose of zyrtec or benadryl can be used even if it doesnt return.
If the rash does return then we will have to consider other issues such as an infection like yeast (which is usually rare in men). For right now i would say use the OTC antihistamines, monitor the location and see if it worsens or not. But from the looks of it it seems to be subsiding even more. It is likely that it was due to an irritant, that can a soap, bodywash as you said among many other things.
I think you will be fine as the irritation is almost not noticeable in the picture.
Do you have any more questions?
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