Apple Watch series 1 pairing/ touchscreen issue

Hi, I have a series 1 watch that had a swollen battery. I replaced the battery and it powered up all good, if I touch the screen it shows date time etc like connected but it’s unpaired from the watch app. It started the unpairing and said it was unsuccessful but now I’m stuck as the screen won’t work to unlock and use it. I can’t use settings in watch app as it thinks it’s unpaired. Can’t find it in the iCloud to remote erase and start again. No idea what it could be connected to! Don’t know the best way to proceed? Assume it’s a hardware issue and look to replace force touch or is there anything else I can do?