Hi
Operation of the Digital Crown can be affected by substances like dust or lotion, but it may also become defective.
If it is not operating as expected and if the issue persists after following the instructions here:
Cleaning your Apple Watch - Apple Support
Then your Apple Watch may require service.
I suggest that you contact Apple Support (remote diagnostics and/or mail-in service may be available, if required), make a Genius Bar reservation or visit an Apple Authorised Service Provider to arrange for your Apple Watch to be checked and, if required, serviced: