BB in neck
I'd suggest reading the op report and find out what was done.
Read in your CPT book the paragraph above the 20100 code. Codes 20100-20103 describe "exploration," "enlargement of wound," "extension of dissection" etc. It further says "To report simple, intermediate, or complex wound(s) that do not require enlargement of the wound, extension of the dissection, etc., as stated above, use specific Repair code(s) in the Integumentary System section."
You may be "on target" with your choice to use the removal of foreign body code you first suggested. Before using 20100 be sure the op notes document the description required for the code. Hope this helps!