Can repair by gluing. But for more permanent fix is via stitching. Gluing method shows how cheaply made these shoes are.

Somehow your feet got bigger..... I wonder if you know that your feet expands throughout the day the more you stand and walk. You can gain half inch all round at the end of the day. And it goes back to normal size as you relax.

Thats why when buying shoes, buy after work or sometime after mid day because the foot would have expanded.