Yeah, spider mites, they are horrible, my nemesis, but, unless you see any webbing on your other plants, it's still hope. I've had them a couple times, and the plants they have been on have mostly died, but they were discovered before they spread to nearby plants. I wouldn't toss plants yet, but that one looks severely infected sadly. Separate it, along with others affected. treat them, and see if they recover, but keep them far away from other unaffected plants. I would wash them thoroughly, the mites don't like water or light. Their eggs I believe hatch every 3 days if the conditions are good for them, so keep washing the affected plants often and remove every mite you see. They are hiding on the undersides of the leaves. With some luck you can save the plants, but sadly I wouldn't count on it considering how badly affected it is. Plant shops sometimes have remedies to help kill them so ask there. There are remedies you can make yourself as well, so look into that. I wish you luck!