B2K Singer On Long Road To Recovery From Hand Injury

As TMZ first reported, Raz B accidentally fell through a glass door in his hotel room in Shanghai, slicing his wrist wide open and losing a scary amount of blood.

Raz B tells TMZ he lost count of how many stitches it took to sew him up ... but says doctors will remove his patch work sometime next week.

Raz says he's still experiencing numbness in his fingers ... and doctors have told him it could take at least three months until he regains full functionality.