My thoughts are it depends on the artery severed , if its a small brach it might not need vascular reconstruction surgery unless its a large major one. The hand looks pink, can you feel both pulses,how is the ROM, nerves intact ? If all within normal range place sutures under lidocaine & dress wound ,Paracetamol PO for pain ,advice to move the fingers frequently per day, return to ED if any changes show. But Ofcourse most importantly is to call for vascular/hand surgeons consult.