Is this normal after a salt bath?

[Abbitha]

So I got a new female guppy maybe a week ago to make a better ratio boys to girls in my tank. She's in QT but I noticed a white growth on her side and head. I dosed with Pima fix and melafix for a few days but it was growing worse So I gave her a salt dip and when placing her back in the QT she now has a huge hole where the white stuff was on her side! It's just flesh now but it's a good hole in her side. She looks fine otherwise. But now I feel like she will be susceptible to infections or something.