Much like sulfur, I find minor skunking can dissipate. I've made a farty beer before (many years ago) where I recall telling my friends "pour it into your glass, then walk away for 5 minutes, then come back and enjoy". Mercaptan compounds are of course volatile so it makes sense to me that in some cases you could do the same thing to a slightly skunked beer -- pour, walk away, come back and enjoy. Or, just embrace the skunk.
I'm with Dave. I've also had many cases where some very light skunkiness up front would dissipate, but it was always faint to begin with. I find sulphury notes to dissipate quite often, while esters, oxidation, and phenolics tend to intensify over time.
I always make it a point to revisit aroma after evaluating flavor and before recording overall impression to check out whether the aromas lingered, dissipated, or intensified. I'll often add a note on what changed (or didn't).
<Hint to prospective BJCP examinees - GRADERS LOVE TO SEE THIS ON AN EXAM (and on competition score sheets)>
I always revisit during the course of evaluating a beer in judging. If nothing else, temperature alone can change things (or allow things to be perceived more readily). My comments typically include "initial notes perceived", "later hints picked up as the sample warms", "final aromas presenting themselves late", etc...to me this is as important as low, medium and high perceptions. it also tells the brewer that I wasn't giving it a mere "drive by" or "quicky" analysis. A good judge told me once that competitions won't survive unless you give the brewers something for their money, even if they don't place an entry. I still write explanatory comments on the NHC "check the box" form, also, for this reason.