Probably not. If you're not getting chafing on your soft tissue or a bruised feeling on your sitbones, your chamois is probably fine.

Some shorts advertise chamois that has antibacterial properties, and those might help with the problem you're having. But for myself, I'm strongly against the carpet-bombing approach to bacteria. It seems like every day we learn about another way that we're paying for that approach, with more resistant bacteria, less beneficial flora, and more compromised immune systems (more allergies, more autoimmune disorders, more cancers).

Especially since you only got the bumps after an unaccustomed long stint in the saddle, if it was me (and actually right now it is me, too ) I'd just treat them and not worry about it.