I want to pass on something that a Sgt. in Infantry Training School told me when I was an 18 year old PFC. The Corps will issue you everything you need, but they will never issue you a new body. It is the duty of every Marine to take care, as best they can, of the one they have. If you are sick, go to sick call. If you broke something, get it fixed. Going down range at less than 100%, is dangerous to you, your fellow Marines, and the mission. Sure, you may be able to suffer through a bout of the flu, a bum ankle, a bad knee, etc. in the field in peacetime, but the conditions in wartime take a toll that no peace time maneuvers ever will. The strange and hostile environment can turn the flu into pneumonia, that bum ankle can give out, and a bad knee can become permanently damaged.
Cellulitus is serious, and the Corp does not mess around with it. They want it healed so they can get your son back into training. Semper Fi to your boy.