Police and ambulance crews were called to the scene at around 2.30pm on Saturday, January 15.
Jack was taken to The Royal London Hospital in Whitechapel, where his skull was glued back in place and he underwent a series of skin grafts.
Doctors say he is likely to suffer permanent scarring, but should otherwise recover from his injuries.
He is already attending the hospital school and is expected to be discharged later this week, but may have to use a wheelchair for a time.
The dog has been destroyed.
Jack’s devastated mum, meals on wheels worker Victoria Devlin, 43, was too upset to speak about her son’s injuries.
Her partner, 40-year-old youth worker Daniel James, lives with Ms Devlin and Jack opposite the block where the attack took place.