Answer: Cordylobia anthropophaga, the mango or tumbu fly.
As Florida Fan nicely outlined, there are several initial features that lead us to the identification:
1. The patient is from Africa, where we can find the tumbu fly.
2. The size of the larva is about one third or one fourth the diameter of the cup, roughly 13-15 mm in length, compatible to that of this fly's larva size.
3. There is no discernible peritreme nor ecdysial scar.
4. The spiracles open through sinuous slits.
The following image shows the posterior spiracles, with the sinuous slits (arrow head). Note that the peritreme is not easily discernible (arrow).