My MMF isnt hardening?

I made it this morning and cut out some polka dots so they could harden....its been all day and they are still flimsy and "melty" I had put them in the fridge was that the mistake? They are uncovered sitting on the table now on a dish....also, they look like bubbly??? Like little air holes had busted in it...is it b/c I rolle dit on a non stick spray?? any advise....