I lost my Apple Watch, is there a app I can use to find it

Hi

The following support articles explain your only options - and the associated consequences - in the event of your Apple Watch being lost or stolen:

• If your Apple Watch is lost or stolen - Apple Support
• Report a lost or stolen Apple product - Apple Support

Find My iPhone, as described with the support articles and Lost Mode are the only ways that you can track, locate and protect a lost or stolen Apple Watch.

Find My iPhone. It will show all devices signed in with your iCloud account, including your watch. Keep in mind that it must be connected to the Internet.

Then there's no way to locate it other than physically looking for it.