Ay, ganyan talaga ang baby diaper rash lagi, lalo na kung sobrang init or kung mahaba nakadiaper nang walang palit! At 5 months pa lang siya, it's pretty common, pero check mo kung gaano kadami ang redness at kung may bubbles or liquid, sometimes it's yeast infection na at kailangan ng special cream. I'd suggest bringing baby to the doctor kung tumatagal or lumalaki pa, kasi alam mo naman kung paano mabilis kumalat ang fungal infections sa babies; a few of us moms nagsuffer din with this and the pedia gave us specific meds na tumulong agad.