Why?

How long the rash lasts is likely to be determined by your own immune system, but I’d be worried about damage to your skin if you were doing this regularly.

Have you thought about trying strapping tape? If you use a medical grade, hypo-allergenic adhesive tape, you shouldn’t have this problem. I think strapping tape would be worth trying. You can buy it from online chemists.

I had to have my foot strapped, and the doctor took the tape off each week to make sure my skin was okay. So I don’t think leaving any sort of tape on your skin for a month is a good idea. If strapping tape isn’t what you want to use, ask your chemist if they have a different type of hypo-allergenic tape you can try.

I would not leave it on that long. Your skin will react very badly to it, not just because it is tape, but because of oxygen deprivation.
I see no benefit to outweigh the potential hazards.

@Myusernamenotyours You are taking chances with the unknown. Duct tape prevents the skin from “breathing”. It is a great spot to have an infection get out of hand. Really great for anerobes. The skin will breakdown at edges of tape. (don’t sweat the rash). When you try to remove the tape if it’s been there any length of time it will remove some skin with it. It is hard to imagine there could possibly be a benefit from this action. Harder still to imagine a thinking person would try this.

Yes, I would like to know why.
Why?
Is this some sort of bizarre weight loss strategy, a secret bondage fetish/compulsion?
As others have mentioned there could be all sorts of complications.

Why? WHY?

That is a very bad idea.

@Earthbound_Misfit The deed is done. Too late to check anything.

Maybe he wrapped himself a little too tight and cut off his circulation. LOL

Don’t do this. First, if you know you get a rash from duct tape you shouldn’t put it on you’re skin at all. Allergies and contact dermatitis often get worse through exposure. What that means is your body gets better at fighting what it sees as an atagonist, and instead of getting red and itchy you can eventually have an anaphylactic response.

Even if you typically didn’t develop a rash, getting the tape off will be difficult, and could peel of some skin.

Don’t do it.

If you already have a rash, clean it well with gentle soap and put some cortisone cream on it twice a day for a few days.

@Myusernamenotyours How is the duct tape working out?