Constipation relief for 4 month old??? HELP tmi poo photo

Yolanda πŸ‘½ β€’ πŸ‡¦πŸ‡Ί | IG: yolandi_b92 | Liam πŸ’™ born 7th August `18 |πŸ’FiancΓ©

- Son didn't poo for three days. Went to the doctor because lower rib was jutting out.

- Dr. referred an ultrasound and xray if that was unclear.

- scans showed son had "minor faecal loading" aka was backed up a little.

- Son pooed the next day, consistency of clay, light green in colour. [see attached pic if you're curious πŸ’©]

- now hasn't pooed for another two days.

- have tried prune juice, boiled and cooled water, massages, warm baths and still nothing.

He is mixed breast and formula fed. Anyone have any suggestions?? Sick of seeing him struggle with a tight tummy πŸ˜”πŸ’”