Hi, I am very sorry to hear your watch continuously restarts itself. Apps you download and install onto the watch can cause the watch to get stuck in a boot loop or not boot past the logo screen. Rebooting it should fix the problem, but you will need to uninstall any apps that were installed before the issue occurred. If the watch is connected to a phone, you must clear the data for the Galaxy Wearable app. If the problem continues, inspect the watch and charger for damage, and factory reset the watch. Try these steps to resolve it: https://www.samsung.com/us/support/troubleshooting/TSG01003223/
Please let me know if this helps.