Also in Hyper Dimension Vegeta didn't have the M on his forhead even though he was distinctly Majin.That's really unfair, the resolution was a lot worse.
I support the suggestion to try and add it at the very end. It's an important part of his design.
If I struggled to the end of my determination, to the end of my way of life with my followers, if the result is ruin, then this ruin is inevitable. Grieve. Shed tears. But you cannot regret.