You won't be able to fully repair the leak from the inside. However, you will be able to patch the leaking area. Once the area is repaired, you don't have to worry about water causing damage to your home. Are patches allowed on the underside? Flashband would work. Assuming that the corrugated steel roof has holes, I would try to repair them from the inside with sections of sheets, putty, and perhaps fiberglass patches, etc.
After all, a leaking roof doesn't provide the comfort and protection that protects the family from bad weather. I used to work in a train depot with a leaking roof above an expensive electrical machine. The repair consisted of a transparent polyethylene sheet extended like an “under roof” with a hose that connected at the lowest point and a hose that went to the nearby drain. If I seal the leak from the inside, it prevents water from entering the house, but it doesn't stop the real cause of the problem (the water is filtered through the roof).
The water then seeps through the space between the roof layers and gravity carries it to the back corner, where it eventually ends up in the house through the leak. If there is no access to an attic or you cannot find out the source of the leak, you can cover it with the plastic roof cover. To do this, it is necessary to trace the waterway that falls from the roof and from there through the attic to the roof. This process requires a lot of patience, as water sometimes travels a certain distance from the leaks before falling down the roof terrace.
There's no doubt that you can follow the path along a beam, but sometimes water can follow the floor of the roof terrace. When the rainy days have passed and the sun shines, put on rubber shoes and use the measurements to determine the drip area on the outside of the roof. When the rain decreases, you can return to the roof and measure similar dimensions and then fix the base of the tiles surrounding the leak with more tar.
