Could pain and bulging on top of foot be a sign of dvt? recently went on a long flight but my d dimer was negative.

Not usually: Usually DVT's cause pain, swelling and redness in the calf area, not the top of the foot. Did you have an ultrasound when they did the d-dimer? An ultrasound of the veins in your calf is a reliable test for DVT.

Pretty unlikely: Having a negative d-dimer makes it unlikely that you have a DVT. The symptoms of pain and bulging on the top of the foot is also not consistent with a DVT.