Brown spot on cactus

[angwu01]

Hi guys, cactus newbie here! Recently I've noticed these brown spots growing on my cactus (photo below), and I can't figure out what it is! I tried to search online, some say it might be bugs or fungus.. I've picked them off and they seem to be hard, but some videos say if it's a bug, it should be soft? I've tried to spray the area with rubbing alcohol solution (part alcohol, part water) but it doesn't seem to have an effect. I'm a first-time cactus parent and I'm scared I've ruined it!

Any advice is appreciated!!

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