It will take a while to heal, but you need to try various things asap, before she gets problems on the other side as she will be using more of her muscles etc on the other side to compensate for the pain.
ALWAYS wear shoes in the house, no barefeet on hard floors.
No ballets/flats. Needs comfy soles, fit flops and birkenstocks are great. Custom made inner soles really helped my son.
Boots also do good inner soles, to keep the foot balanced and in the correct position.
Buy a bottle of tango, empty or drink and then fill with water and freeze. The shape of the bottle is really good to use as a roller under her foot. It keeps massage the area. Ditto tennis ball or one of the spiky pilates balls.
Good exercises can be done on the edge of the stairs. Stand on tip toes on the edge of the step, holding onto hand rail. Raise both feet up and down a few time, then alternate the feet. Then drop both heels and raise, again alternate. Morning and evening.
A physio can do a really good foot massage and get into the right areas deeply, also they can use the ultrasound machine, that really helped me, it breaks up the problem inside the foot.
Rest from PE and Sports for a while, it needs rest and gentle exercise targeted at the foot. Also massaging the calf muscles helps, as if they are tight it pulls on the foot muscles. I used to have to massage my son's calf muscles every morning before he got out of bed. You could feel the knots.
Also check the diagnosis, ie second opinion, that it's not Severs .
physioworks.com.au/injuries-conditions-1/severs-disease