it is most probably extensor tendon inflammation . Rest until the pain has gone. Apply a cold therapy and compression wrap. Apply ice of cold therapy can be applied for 10 minutes every hour initially reducing frequency as required over the next 48 hours.Once the initial painful acute stage has passed then application of heat may be more effective. Ensure footwear is appropriate and in particular the shoes are not laced too tightly. Over tightening the laces puts direct pressure over the extensor tendons in the foot. When all pain has gone a full rehabilitation program to strengthen the extensor muscles should be done. by doing certain exercises to strengthen