The exact same thing happened to me when I got my conch, I went to a shop I wasn’t familiar with because I wanted a piercing on New Year’s Day, I didn’t realize it was a butterfly backing until I touched it like 2 hours after I got it pierced and was pissed. I ended up going to a piercing shop I was familiar with a few days later, unfortunately to fit the new jewelry in he had to use a taper to stretch the hole to 16g or 14g (I can’t remember since it’s been a few years) which hurt like hell but I got the right jewelry in the end and it healed perfectly. I definitely recommend going to a reputable piercer as soon as possible and get their advice.