I have one of my Loaches with a little "Boo-Boo" on his nose.His is definately from digging like a mad man.
Pristene water is a key factor for it not to go bacterial.
The thing about salt,is that Dojo's are considered "Scaleless fish",and most times you hear that salt isn't good for them.I personally don't salt any of the tanks that my Dojo's are in,but I have heard quite a few people say that they can withstand low doses of salt to 0.1%,and that their Dojo's did fine with that.
I guess it comes down to what you decide though.If you do decide to salt,make sure it's at a time when you can be around to watch over their reactions,etc,and deal with it accordingly.Slow dosing that 0.1% probably would be better.that way,if you see them start acting out of sorts,you can be there to start changing out water.
If it were me,I'd probably do the pristene water and the Medi-Gold.
Anyway,good luck,and I hope the little guy will be fine.