I'm not an expert , but if I mess up the dyeing, I take methalated spirit and a cotton pad , with a little bit of luck you get all the dye off .
Before antique my leather , I use 2 ore 3 thin coats of super shene .
I don't like to start again and gave it a try and for me it worked.
Did the same to get of the wax and color off my 20 years old saddle in combination with L.O.C from amway to get all the dirth off 20 years using it off.
The leather could soak , water again , so I could carve it , and painted it another colour.