I am on blood thinners and today i noticed a very tender bruise on the bottom of my left foot. it feels hard to touch could it be a clot?

Bruise&BloodThinners: Blood thinners are often used to treat those w/blood clots & to prevent strokes. However, they do increase risk of bruising & bleeding. Assuming taken as directed (and at therapeutic dose), it's unlikely for tender bruise to represent a clot since that's what blood thinners prevent. Still it's a good idea to get examined by prescribing doc & reassessed if continued need for blood thinner.