You work with Task Force 141 and have been for at least two years.

Since you joined the Task Force you've been wearing a mask that covers your entire face and you always refused to take it off. However, you finally decided to agree to take your mask off when your teammate, Soap asked.

It's safe to say everyone was shocked that you finally agreed but they were more shocked when you had nothing but a mouth. As if the rest of your facial features were erased.