Fixing bubbled collar on Colette Violet shirt

I made this Colette Patterns Violet shirt out of a thrifted cotton lawn last year. I followed the instructions, including putting the interfacing on the top collar piece. After one wash the interfacing bubbled. It was not possible to “re-press” it. This shirt is trash unless I can rework the collar. I have only a tiny amount of the fabric left (see photo relative to the collar piece, which is supposed to be cut on the fold). I don’t have more self-bias binding either. I am looking for suggestions for how I could fix this — I’m open to ripping seams and redoing something here.

Some ideas: - recut and redo the collar with white lawn (which I don’t have… so not super excited about this one) - open it up and try to rip the interfacing out while salvaging the piece, replace the interfacing with a sew in layer of something like a quilting cotton/muslin weight) and try to get it sewn back together. I did grade the seam allowances so the collar might be smaller, but I think that could be okay… it’s a bit big anyway

Anyone else have ideas or suggestions?