Tom Walker, Just to add to Ged's good answer, find below a video link showing how to change the glass/digitizer and a couple links to possible replacement glass/digitizer, which you can also do a search for possible better pricing. Good luck. I hope this helped you out, if so let me know by pressing the helpful button.
https://www.youtube.com/watch?v=LvWPfUhphcg
https://www.etradesupply.com/apple/apple-watch/apple-watch.html
https://www.amazon.com/FONREST-iWatch-Digitizer-Screen-Replacement/dp/B00YSJNCTA