OK, the fact that the area around the mouth are wet is concerning. Tarantula setae are waterproof, they don't absorb water. So, even after drinking the mouth area should still be dry. Here is where I am going with this. Her behaviors, and symptoms are very compelling for nematodes. Refusal to eat, constant drinking, sitting in or near water, standing on "tiptoe", repeated methodical cleaning of the mouth and fangs, fangs held loosely open not tightly closed like normal.a discharge, sometimes milky in appearance, and crusty formations around the mouth and fangs. Since she does not seem to have any discharge or crusting, I could be, I hope I am, wrong. Give her a new, clean water dish. Watch her, and as soon as you see her drinking, let her finish then take the dish. Pull a sample of the water and place it under a microscope, or you can use a magnifier app on your phone, and examine the water for small (1mm) thread-like organisms moving about. If this is the result of nematodes, you must quarantine her immediately. Nematodes can spread through an entire collection like wildfire. It is nearly always fatal. There are only a handful of cases where a keeper managed to save a tarantula. I did not not want to mention this until we had more evidence, as I did not want to panic, or scare you. However, I think you ned to know what you may be looking for, so you can, if this proves positive, take immediate action to help her. A link with details for you: http://giantspiders.com/article12/ The TKG also has a good bit info on nematodes.