I got shocked by my Apple Watch and it left a welt bruise on my arm. Apple Support has insisted it's just Static Electricity.

never heard about a shock before, read posts about people saying they got burned or allergic reaction but never a shock

if they will not listen to you then you can use their feedback channel Feedback - Watch - Apple

Hello,

Thank you for participating in the Apple Support Communities.

We want to make sure you reach the right team for help with your device. We recommend that you contact Apple Support directly. Depending on your region, you may be able to reach them here: Get Support.

Have you had the battery checked? Low battery health has caused mild shocks in the past. While it isn't possible for Apple Watch to electrocute you, shocks can certainly be painful- but if you don't want to wear it, it can still be used as a clock if you want (on its side), or sold/traded in, perhaps.

By submitting feedback, you've really done all you can. Your next step is deciding whether or not you want to continue wearing Apple Watch, I think.