Did you wash your resin first?

resin getting soft migh be that your paint wasent mixed well enouph and too much thinner got on. i.e laquer thinner will softer resin. Its always good to prime firt to protect the parts. you might still be ables to stip the paint and start over.

or maybe try to dry it with a hair dryer on low heat setting moving around alot not to let it heat up too much