So I have changed my name today for free, and I didn't know it would change my numbers from #0000 to #2025. I was wondering if there is any chance or reverting the change or getting my number back.

not possible

sorry to say it, but it isn't possible anymore :(

Sadly it is gone, you would not be able to get it again

Hello,

There's no way to get the #0000 tag back after changing your username. The only way your tag will change now is if you change your username to a name that is already taken with the exact same tag.