Aww mama, hindi ako familiar sa ganitong bumps, pero a month is quite long para sa insect bites, I'd really suggest bringing baby to the pedia to check kung ano talaga yan, baka may infection or kailangan ng special care lang. It's great na hindi masakit when you touch it, but better safe than sorry with our babies, right? You're doing the right thing by observing it closely and asking around, that's good parenting! I'm sure the doctor will give you peace of mind agad, at likely it's nothing serious. Laban, mama!