I have not seen regular skin texture brushes work very well either...because you dont seem to be able to overlap them very well...the brush solutions dont blend very well for some reason. I wish they did. It would be very handy.
Over the years I have been able to create sheets of skin pore textures for myself using a very special model here that has perfect skin. I use these repair skin textures to fix up the skin softening problems that I run into. Like you, if Im doing lip work, or retouching under the eyes, the cheeks, or trying to thin out eye lashes...I end up with areas that are overly smooth and eventually loose texture. Its these areas that stand out and call attention to themselves. For skin to look right... it needs to have the proper underlying skin luminance level that matches, proper matching color hue and saturation, and especially... matching texture.
I made up a video clip a while ago that shows fixing up skin pores with this kind of technique so some of my friends could see it. I still have the link. Here it is: http://www.screencast.com/t/wIHk5WI0yyIG
(You can enlarge it to see better). You can look at it and see if this is the same kind of skin pore issue you are having. You specifically mention the top of the lip area in tight closeups...thats the first example in the video. I dont know if that is what you are looking for or need.
I would be glad to specially meet up with you sometime and I would show you how you could do something similar in your case. I know its frustrating to have great images but the blotchyness and lack of texture ruins the look. You can PM me here at Mayhem. Ill be south of you in London next week...or we can meet on-line too.