The belt section is fine. It where the watch itself rests. I wear for only 9 hours a day, mostly when going to work and I never sleep in it. I always clean the band with alcohol.
I'm sorry for the troubles with your wearable. It looks to me to be defective in some way. It could also be an app causing the issue on the watch. To be honest, I haven't an idea how to get the thing into safe mode. But I would start looking at the apps you downloaded recently.