My girls get a little stinky once in awhile, sometimes my oldest doesn't wipe well enough and I'm sure I've missed a spot once in awhile when cleaning my youngest. I do the following for a day or so and if it gets worse or doesn't clear up then I go to the doc.
1. Wipe her again very well
2. Give her a good soak in the tub with water only (you could do this a couple of times in one day if you want)
3. Change her a little more frequently and keep her extra dry. Let her bottom air dry before putting the diaper back on or dry it w/a cloth. My daughter can't be left w/out a diaper, never fails she goes on my carpet, so I dry w/a cloth.