Give it a go -- not sure it it'll work for you or not.
I don't normally powder noses, but applying digital eye shadow and blush are done differently.
Printable View
As has been suggested I do sometimes use the eye dropper to select the colour as close to where I want to replace and then paint over the unwanted blemish. Only really useful in areas of a single coloured background. You can sometimes get away with using the tool for drawing a shape around the unwanted item, leaving the marching ants around it, then right click inside it, choose 'Fill' and select 'Content aware', which will often choose to replace the area with similar to what surrounds it.
The quandry I often find is if I choose the cloning source too far away it is a different shade and if I choose too close to the area I want to replace I trip over myself and clone the unwanted item elsewhere :)
My tupence worth is to wipe as little as possible but click a stationary area with a soft edged brush at low density and low sharpness. [ PSP is different in this respect with more controls offered than the PS I have used ] Keep on re-setting the pick-up point to avoid transfering recognisable features. Or clone on clone when this happens.
A useful feature is that it is possible to pick up from one layer and paste onto another although this is tedious changing between layers.
In addition to using the clone tool it is also worth considering in some cases the duplicating of whole areas to hide some unwanted feature. I would select an area and copy it as a new layer placed over the background layer, perhaps increasing the canvas size to make room for it on at least one occasion I can remember. Wedding group shot tight with 3:2 format and clients wanted a 10x8 print ... added some grass for the foreground and more trees across the top.
I should add that my advice was for CLONING (ie clone stamp) - more often than not I use the healing brush - patch tool - and content aware fill, each of which have their own peculiarities.
Content aware fill is fantastic for many removal jobs; for things like spots in the sky, you can select them all and then have content aware fill zap them all in operation.
Pretty much the same in Photoshop. The "trick" is to use about 12% opacity - re-sample between strokes, but be sure to (a) stamp into a new layer (so you can erase the over-painting), and (b) be sure to paint in the right direction (and from an appropriate source) to keep the "flow" looking consistent (ie "don't stamp across the grain").