is it only at the bottom where you pruned? degree of herm is relevant. Pluck'em and hope for the best. If it was stress and no longer an issue, shouldn't pop more. If it's predisposed in a severe way, it won't stop. If a little heat caused it, i'd still lean toward genetics being the real problem. context matters... won't always be exclusively one or the other.
If considering outside sources rather than genetics, they take ~4 weeks to grow and open up. So, if caused by stress it would have to precede that timeframe.