making sure this is safe.

[stoic girder]

i have a surface pro and it has a bitlocker that i dont know. i have a usb with windows if i boot to the usb will something bad happens!

[mental steeple]

If you mean that your drive is bit locker encrypted and you don't know the pass code, you should be able to use your recovery key, assuming you kept a note of it:
https://support.microsoft.com/en-us/windows/finding-your-bitlocker-recovery-key-in-windows-6b71ad27-0b89-ea08-f143-056f5ab347d6

If you don't have the recovery key, as far as I know there is no way to access or recover your data. Booting into another install will still require you to know the password
https://answers.microsoft.com/en-us/windows/forum/all/how-to-unlock-bitlocker-encrypted-internal-fixed/737a68d3-80ae-4b7f-87ae-806c4f87910e