"Some individuals have found that dilution of methylene blue (2 mL of methylene blue and 3 mL of saline) allows successful mapping while avoiding this local toxicity (Pat Whitworth, MD, personal communication, May 2004" -- from second reference article.
Treatment consists of basic wound care.
1) Keep the wound clean.
2) Keep the wound moist.
3) Keep the wound well nourished, which implies reducing or eliminating edema and keeping pressure off the wound.
4) Debride only as necessary, be conservative.
Methylene Blue Solution for Injection Data Sheet--MedSafe