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I did check but I also asked on chatroom bout this and they said since Magic Guard doesn't say it prevents rough skin in nda spreadsheet, the user takes rough skin damage
21:06:26 <ASBot> This Pokemon is infused with a powerful psycho-electric energy that makes it immune to damage from Spikes, Stealth Rock, Hail, Sandstorm, Leech Seed, Poisoning, Burn, and Partial Trapping moves. It can still attack itself in confusion, and will still take damage from it. Additionally, the energy protects the Pokemon from its own reckless recoil attacks. Toxic still increases in damage each round, although if Magic Guard is in effect the ...