Recently, I got up to lvl100 and I realize I really need to "HP WASH" my character. I have 3265hp and 2174mp and just wondering is it worth to do although I'm lvl 100? Please help me out!
Sure it's worth it. It'll help you at bosses such as horntail, and you'll be able to tank anego's ranged attack earlier. Asuming your base MP is 2174 you can already wash about 52 times.
Yeah, make sure it's base MP and not total mp you use to calculate with. (thus no items that give mp included: such as xmas nose, slime ring, dep star). After that you can use http://royals.ms/forum/threads/hp-washing-reference-table.17093/ to know how much you'll roughly get and how much mp you'll need.