Maybe she used what she thought was bi-carb... she's scottish so could've thought it was different who knows. I might give it a go, it's not as bad as it was. We do use only QV oil in his bath but he still has the under chin/neck thing which is getting worse ... gets it behind his knees too and his wrist roll but only on one side lol. I have about 3 boxes of it so might give it a go! Thanks
This normally happens when the skin is not dried properly and moisture gets trapped in the folds.

Make sure you really try to dry the areas thoroughly and during the day watch for milk getting trapped in his neck creases as that causes it to go yukky as well.

HTH