Sometimes multiple slits help. Also you might try heating it up and use a soft cloth to GENTLY rub down the bumps. A pin hole in trapped air bumps helps too. the small TRIM monokote iron is a good tool for these kind of tight spots. I did notice your wrinkles or bumps are on the flat part.
Iron down all the flat parts first and sheild the area with cardboard or whatever then do the curve as you did before. this way the flat stays put, if its hot it can pullaway making wrinkles.
I give GREAT advice as long as when you look at my planes you keep the 10 foot rule in mind.

IF YOU CAN'T SEE IT FROM 10 FEET ITS PERFECT!