Apple Watch faces are not supposed to be able to do this. Certain apps have a zoom feature, such as maps, but not Watch faces.
Have to tried restarting your Apple Watch? Press and hold the Digital Crown and side button until the Apple logo appears then release and wait for the restart.
My watch does the same and I must do a restart to get it to act normal again.
I haven’t found out what is causing it to get stuck like this.
Hopefully it won’t happen again after the last update in watch os that was installed this week.