Rubberized door handle area

I have a 2000 Nissan Maxima.

Door was removed as part of body work. Repair person

must have gotten a solvent on rubberized portion of inside door area

next to handle. It used to be hard plastic/rubber but now soften area.

Any product to harden this back? Especially in summer soft.

Cost too much to replace door panel. Whole panel would need to be replaced.