There is a color change on Darkman's burned skin. In the beginning of the movie, in his lab, his burns are pretty much flesh colored. Later on in the movie, they are a much darker red and brown.
Executive Producer Sam Raimi reportedly told co-star Larry Drake that despite his character Durant being killed off a second time at the end of this film, there were plans to bring him back in a later installment once again. Essentially, Durant would become Darkman's version of the Joker or the Green Goblin- a recurring arch-nemesis that never "truly" dies, and is always brought back to life one way or another. Unfortunately, after the release of the third film, no further sequels were commissioned, so this idea never came to be.