Following text is from a link which summarizes most of problems the dancers have by placing much pressure so often, link.
There is a lot of jargons.
"The collateral ligaments of the lesser metatarsophalangeal joints can be torn by a dorsiflexion sprain or, in an older dancer, can be stretched out, slowly leading to instability in the joint".
Smaller ligaments of smaller toe joints can be torn by sprain involved in stretching at the end. There is no difference between stretching or tear of ligaments.
"When the dancer relevés onto the ball of the foot, the base of the phalanx subluxes onto the dorsum of the metatarsal head, forcing it downward (the dropped metatarsal), leading to metatarsalgia. When the dancer comes back down to the floor, the phalanx relocates and appears normal."
This means when your habit of doing this exercise strongly and causing the damage, afterwards, it looks normal but the damage is done.
"The regular set of X-ray films will also be normal. To pick this condition up during the physical exam, you must do a Lachman test on the metatarsophalangeal joints. This test is similar to that which is done on the knee. When you test the joints in this manner, the affected toe will easily dislocate and then relocate, making the diagnosis apparent."
This says metatarsophalangeal joints are so loose that you move parts of these joints and see them moving too loosely. Given minimal time doctors spend with you and they don't know exactly what is normal for you, it would be up to you to describe what is normal. Dancers brag about how flexible they are, this is exactly how you damage youself by making yourself even more flexible.
Once the ligaments are loose, you cannot tighten them without surgical intervention. Sometimes flexion exercises and a toe retainer with padding under the metatarsal head will at least make the problem workable.
The subluxing cuboid is a common but poorly recognized condition. It presents as lateral midfoot pain and an inability of the dancer to work through the foot, i.e., go smoothly from foot flat to relevé. This condition may present as an acute sprain or an insidious overuse injury. The dancer is unable to run, cut, jump or dance without a marked increase in discomfort or a feeling of weakness and lack of intrinsic support in the foot. Pressing on the plantar surface of the cuboid in a dorsal direction is painful. The normal dorsal-plantar joint play is reduced or absent when compared to the uninjured side."
This says, you stretched it too much and it requires an operation to shorten stretched ligament. It also tells you can dance but can't improve or achieve optimal activities.
"Severely subluxed cuboids leave a shallow but definite depression you will see on the dorsal aspect and a palpable fullness on the plantar aspect of the cuboid. Treatment usually involves a manual reduction called the cuboid whip. This reduction should be performed by a practitioner who is familiar with the condition. You may also need to repeat the maneuver."
Please read this article, link.
Definition of subluxation from Wiki
"An orthopedic dislocation of any joint will never need medical attention to help relocate or reduce the joint. Nursemaid's elbow is the subluxation of the head of the radius from the annular ligament. Other joints that are prone to subluxations are the shoulders, fingers, kneecaps, toes, elbows, eyebrows and hips affected by hip dysplasia. A spinal subluxation is relatively rare, but can sometimes impinge on spinal nerve roots causing symptoms in the areas served by those roots."