Madeline is a 4 month old baby who is fully breastfed. Her mother gives a one week history of her being very unsettled for no apparent reason. She will cry for around half an hour despite being held and this is worse towards the evening. She describes Madeline drawing up her legs as if in pain. Between these episodes she is happy and gaining weight well. She will sometimes bring up small amounts of milk following a feed but there is no vomiting, and her bowel movements are as normal.
Based on the likely diagnosis, when can you advise her mother this is likely to settle by?