Pea Size Bump at the back of th3 Head

Hi guys have you experienced having discovered that there's a bump at the back of your childs head? magkabila yung prang skin na bump mai appointment km sa pedia niya pero next day pa .Kinakabahan ako kasi baka ano na to sa anak ko lalo nat sa ulo .Hindi naman namaga or nag red tapos kung hawakan hindi naman naiyak si baby.#1stimemom .Thank you for answering.