I bought this donkeys tail about 2 months ago and its looking healthy until I get close to it. I have noticed that all the new growth is shrivelled and so at first I thought it wasnt getting enough water. I've given it extra water and it's been through 2 water cycles but it just seems to be worsening :(

on closer inspection I have noticed that quite a lot of the leaves particularly on the denser side of the plant have these brown dots on them.

The lower stem of the shrivelled new growth seems to be completely dried out, it's very firm to the touch. I've tried to get a good picture of this. I've never owned a donkeys tail before so I don't know what to do.

I am fearing spider mites as I've noticed very fine webbing on the plant too, one of the pictures shows this. could the shrivelled leaves be because of mites and if it is what can I do to get rid of them.

im really worried about this plant, it's so thick and beautiful that it would be such a shame for it to die :(