the maid-servant of the Messenger of Allah (ﷺ), said: No one complained to the Messenger of Allah (ﷺ) of a headache but he told him to get himself cupped, or of a pain in his legs but he told him to dye them with henna.
Declared Hassan By Imam Albaani
Imam Ibn Baaz was asked about men using Henna especially as a treatment, he replied:
“We don’t know of any problem in regards to it being used as a treatment. As for using it as the women (use it), then it isn’t permissible due to that being an imitation of them. As for if the man uses it by way of using it to treat a illness in his foot, or hand or other than it, then there is no harm in that.”
Majid Jawed Al-Afghanee