The AIM contains guidance on LAHSO operations and specifically says (in bold; I didn't add the emphasis in this case) that the clearance does not stop you from going around, but if one becomes necessary, the pilot should avoid other aircraft and vehicles and notify ATC as soon as possible:
AIM 4-3-11 Pilot Responsibilities When Conducting Land and Hold Short Operations (LAHSO)
5. If, for any reason, such as difficulty in discerning the location of a LAHSO intersection, wind conditions, aircraft condition, etc.,
the pilot elects to request to land on the full length of the runway,
to land on another runway, or to decline LAHSO, a pilot is expected to
promptly inform air traffic, ideally even before the clearance is
issued. A LAHSO clearance, once accepted, must be adhered to, just
as any other ATC clearance, unless an amended clearance is obtained or
an emergency occurs. A LAHSO clearance does not preclude a rejected
6. A pilot who accepts a LAHSO clearance should land and exit the runway at the first convenient taxiway (unless directed otherwise)
before reaching the hold short point. Otherwise, the pilot must stop
and hold at the hold short point. If a rejected landing becomes
necessary after accepting a LAHSO clearance, the pilot should maintain
safe separation from other aircraft or vehicles, and should promptly
notify the controller.
And because I hear some pilots get the readback wrong, the next paragraph covers the proper way to read back a LAHSO clearance:
7. Controllers need a full read back of all LAHSO clearances. Pilots should read back their LAHSO clearance and include the words, “HOLD
SHORT OF (RUNWAY/TAXIWAY/OR POINT)” in their acknowledgment of all
LAHSO clearances. In order to reduce frequency congestion, pilots are
encouraged to read back the LAHSO clearance without prompting. Don't
make the controller have to ask for a read back!
If there is any doubt, don't accept the clearance in the first place. If something happens after you have accepted it and you aren't positive that you will be able to hold short, go around as early as possible to maintain as much separation from whatever may be crossing your runway.
There is a lot more guidance in that section of the AIM which I would highly recommend that any pilot flying in to a large airport reads.