Unless the wound is gaping open and structures under the skin, such as tendons, it is not necessary to do anything. The wound will heal by what is called secondary intention. The wound will start to heal at the bottom, and then, gradually granulate in.
Also, by this time, the physician would not attempt to close the wound this sutures anyways. The chances of causing an infection would be too high. Contrary to what most patients think, closing wounds after about 6 hours or so after injury, will actually cause more infections. By that time, the wound will have been colonized with bacteria and closing it, just closes the bacteria into the wound.
Thus, wounds are left open all the time and they heal very well. We tend to suture wounds now days, to help them heal a little faster and to have a better looking scar. But, except for rare cases, all wounds will heal on their own, if just kept clean and allowed to do their thing.
So, you just need to keep the wound clean with plain old soap and water. Try not to soak the wound in dirty dish water or the bathtub. It is okay to get it wet in the shower, to wash it. If you want to use a little hydrogen peroxide, that is okay.
As to ointments, if they are used, they must be kept to a very minimum. Do not goop it on. And, it must be removed everyday and the wound washed. Do not just keeping adding ointment, without cleaning the wound. That will trap bacteria under the ointment and could cause an infection.
After cleaning the wound, just place a dry dressing as a dust cover. Not much else is needed.