The darker colours dirt outside of the cleared area is perhaps 'sweepings' from the cleared area, swept by the brush.
The water droplets are blueberry-like things/structures within the rock itself or patches of different material embedded within the rock as it was formed. I do not think what we are looking at here are water droplets.
I suspect that relative "downhill" is top left and so the sweepings of the brush have all fallen that direction and the raised 'drop of water' that you point out in the first picture could be directing the sweepings into a finger-like shape which you think maybe caused by water or damp dust.
I am not necessarily correct on this, so you just have to consider it and see what you think.
Bear in mind that the sweeping was done and then a picture taken afterwards, so there is not much time for water to accumulate - even if it is raining, on the rock which has just been swept.
I have seen larger disturbances of soil in other areas which I think is caused by something digging up the ground, but I think this area is recently brushed and so I would assume that most of what we see here is either natural to the rock itself or caused by the sweeping action of the rover's brush tool. (Is it called the RAT on Curiosity? Maybe not.)
This image from the Mars Hand Lens Imager (MAHLI) on NASA's Mars rover Curiosity shows the patch of rock cleaned by the first use of the rover's Dust Removal Tool (DRT).
The tool is a motorized, wire-bristle brush on the turret at the end of the rover's arm. Its first use was on the 150thMartian day, or sol, of the mission (Jan. 6, 2013). MAHLI took this image from a distance of about 10 inches (25 centimeters) after the brushing was completed on this rock target called "Ekwir_1." The patch of the rock from which dust has been brushed away is about 1.85 inches by 2.44 inches (47 millimeters by 62 millimeters). The scale bar at bottom right is 1 centimeter (0.39 inch).