What did I do wrong and how do I fix it?

Or.... toss it and get a new one and start over. LOL!

You could sand, file, scrape but I believe stripping the paint off is your only option.

I've had the Krylon clear coats do this to me. I'm to the point now that when I use any clear coat I hit a small relatively hidden area with a short blast and check out the results.

Simple Green, Purple Power or one of the other heavy duty degreasers.

Easy Off- "gag, cough-cough!!!". This stuff is nasty. Use a respirator in a well ventilated room or outdoors.

Brake fluid-I've never used it but evidently it gives good results.

I use a tooth brush ($1 for 5 at Family Dollar) and a green 3M pad to help remove the paint once the model has soaked.

These may all take several days and repeated applications. You usually still have to hit some areas with a file or sandpaper.

BTW, latex gloves are a must for all the above

Ouch, been there, done that quite a few times. The only solution I know of is to strip the paint off with Easy Off oven cleaner. There's also an automotive brand cleaner that does the trick, but I can't remember what it's called; I'm pretty sure someone will be by to fill in the blank. Good luck!