Hi Amounir3,
We understand that your Apple Watch's screen is blank, and we want to help. It sounds like you already did some good troubleshooting, and we appreciate that.
You mentioned that the Apple Watch is still responding normally; can you let us know more about that? For example, are you hearing sounds coming from it, or something else?
If the Apple Watch seems as though it's not powering on fully, there are some additional steps and information on the following page that may help:
If your Apple Watch won't charge or it won't turn on
If your Apple Watch seems to be powered on, but the display remains blank, can you let us know if you recently adjusted the "Always On" settings before this issue began? You can find more information about the "Always On" feature, and how to interact with your Apple Watch here:
Use the Always On feature with your Apple Watch Series 5
Thanks!