Call or page the Dr. A 3 month-old baby who is "unconsolable" is fussy for a reason. If the baby had cold symptoms or has fever, an infection is likely. If truly not able to be consoled, the baby should be seen at the emergency room to rule out meningitis. If just "fussier than usual", parents can check the baby with no clothes on, give tylenol, (acetaminophen) give a warm bath, give a feeding, and if still fussy, go to urgent care.
Possibly but.... Most babes get bottom front teeth first. Depending on location these white bumps may be bohn's nodules or inclusion cysts, both normal variations of infant gum tissue that do not cause pain. If these white areas easily rub off then they may be thrush, a common infant fungal infection that requires medical treatment. If unsure see a pediatric dentist.