my bb had chicken-pox when he was 3 1/2 months old. his doctor has prescribed the medicine called Acyclovir for him. but not every baby has chicken-pox needs this medicine and not every doctor will prescribed for that. it depends on the baby's condition. so, you might wanna see the doctor and at least confirm if it's chicken-pox or not. if so, your bb won't need to take the chicken-pox vaccine later.