I have an unexplained bruise on my right wrist, it's probably the 2nd time this happens randomly, what could it be??

Unexplained bruise: Most common reason for unexplained bruise is minor trauma/injury that goes unnoticed. Of course, in older patients (26yo is NOT old), skin becomes more fragile and easier to bruise. After that, review your medications & dietary supplements for aspirin & NSAIDs eg Ibuprofen & Naproxen (both available OTC). If none of the above, then see your Family Doc for evaluation of your blood.