OT, how did that happen??? And it wasn't Brutal Dreamer's fault this time because he didn't say anything....
Neem oil will work fine, as will any kind of insecticidal oil (the oil clogs the mites' breathing tubes and they suffocate.....) But if it's just one plant, don't bother going out and buying Neem if you don't have any. A heavy spray on both sides of the leaves with water outside will usually take care of the problem. Repeat every four or so days for a couple of weeks. But if you want to do something more hardcore, isolate the plant so the mites don't spread to everything else, and then spray the plant with a mixture of rubbing alcohol and a few drops of concentrated dish detergent. (Mix that all up in a plastic spray bottle and then "go to town.")
Repeat the treatment, again, every four days for about two weeks. (The alcohol will kill the mites, but it won't get the eggs. Repeating kills the larvae so they can't reproduce...)
What a drag!!! Sorry they got to the plant. The pitting damage to the plant is, unfortunately, permanent as long as the leaves are around, but the mites themselves are easy enough to get rid of...