I Recently Sliced My Thumb On A Blade At Work.

I recently sliced my thumb on a blade at work. Went to urgent care and instead of stitches, they used liquid stitch. The underpart has healed but there is a slight lump underneath that wont go away. My workmans comp doctor says its scar tissue but it has barely any feeling when I touch but hurts for a good 10 minutes if I accidentally hit it. Ive been keeping it clean and taking antibiotics and was given a tetanus shot. What could the lump possibly be??