You can try some of these hacks to get hairspray off of a touch screen phone:
1. Use a little rubbing alcohol then wipe with a microfiber towel
2. Get a microfiber cloth or any smooth cloth and get a little bit of water or screen cleaner fluid (not windex) on the cloth and wipe.
3. You can use a liquid cleaner like Monster Cable iClean or a glass cleaner.
Of interest, if your touchscreen responds slowly, inconsistently, or doesn't respond at all, follow these steps shared by Apple:
Check your touchscreen
Make sure that your hands are clean and dry, then try these steps:
If you have a case or screen protector on your device, try removing it.
Clean the screen with a soft, slightly damp, lint-free cloth.
Unplug your device.
Restart your device. If you can't restart it, you can force restart your device.
If your touchscreen still doesn't respond like it should, contact Apple Support or take your device to an Apple Retail Store or Apple Authorized Service Provider.