Hello!
Now stay cool - although I know it might be hard to do - maybe you can still save your glass. First question is what exactly did you spray on? If it's not some kind of hot lacquer, then you still have a lot of options. First - clean it up with some solvent - just don't use anything that would damage your glass further. Test the solvent on some scrap material first. If it's acrylic, windex might help you. If it's enamle you might try airbrush thinner (like I wrote, test it first - and hurry, it would only work for the first few hours after application). So, what clear exactly did you use?
The second option would be to polish it out. You would probably need to wait until the clear is really dry, then you can use polishing compound or even toothpaste in a pinch, and tissue and polish the glass. Potentially it can even turn out better than it was before - on the condition that the solvent from the clear didn't eat into the glass too deep.
Hope it helps - let me know how everything turned out and have a nice day
Paweł