Luffy was also nerfed. He was injured and had used haki prior to the fight. Oda made a point to have both Luffy and Doffy acknowledge each other's wounds before they started fighting.
After that Doffy fought Law again and was nerfed, Luffy had no real damage after that, unless we consider Bellamy pounches...
Doffy was more damaged than Luffy, with a good margin too