I have a Apple Watch series 3. There are hard water spots on the screen that I can’t get rid of help!!!!

Please see Apple's official care advice, Cleaning your Apple Watch - Apple Support. Soap won't help water marks, try a soft cloth dampened with warm distilled or deionized water, and try leaving the watch lying face down on the damp cloth for a while to see if the marks will start to clear. DON'T try to use solvents or chemicals unless you are prepared to damage your watch, and don't try to polish the marks away by rubbing. Hard Water deposits are basically like chalk or limestone, - that's right... stone, so rubbing may scratch the watch face.

Hi,

You didn't use screen protector or something?

If you didn't, you'd better make Genius Bar reservation or take your watch to Apple authorized service provider to check it up.

AppleWatch is perfectly working, by the way?