I was thinking about making a Wizard that casts glyphs of warding on his skin (which is a surface) such that any time that I take damage, the source of the damage gets hit with stored fireball spells until they die. My DM said that I could not do this, because my skin does not count as a surface. I know that my DM would be willing to let me do this if I could prove to him that this would work RAW. How do I do this?