paint problem need help please

The paint was hard within a week. When i mentioned being able to dig my nail in, it was after pouring very hot water on the hood and I was washing and tried to dig a little at the contaminated area. I t almost felt like I could scrape off the contamination but I worried about wrecking the clear.There was nothing wrong at all with clear until I let the car sit out under the trees for a couple of months.I am guessing with all the studying I am doing that the sap,dust etc sat on the car got wet and dried very hard?