How to loosen dead fingernail from skin?

I slammed my thumb in the trunk of my car, and the trunk actually locked on my thumb which of course caused the nail to die. This happened beginning of April, and it is now June. The nail is completely detached from one side of my thumb, but still attached on the other side. Is there anyway to loosen the nail entirely? I'm worried ripping it off would hurt more than it needs to. Thanks so much!