How do I treat a cut on my Achilles?

If it is a superficial cut (like from shaving), you would treat it as with any other laceration- antibiotic ointment and bandage. If it is cut all the way through the dermis than you would need to go to the urgent care or emergency department and get stitches. If it is through the skin and into the tendon as well than go to the emergency dept right away. They need to repair that and put you in a splint so you don't totally rupture it which would be a huge surgery and a very long recovery.