Translation:The foot is swelling
I don't think older comments are ever removed. The course developers don't have time to read them, so we have to actually hit 'Report' if we want to get their attention. They are only volunteers and I get the impression that they check the reports in bursts when they find time. Unfortunately, it's a slow process.
I suppose "mguu umevimba" (note: not "li-") could mean either what has happened or your current state as a result. I think the distinction in English is subtle in this case. (When your foot has swollen, it probably still is swollen.)
With some other verbs, '-me-' would always indicate your current state, and you would never use the present tense. (Clearly, it is OK to use "-vimba" in the present tense while your foot is swelling.)
To summarize the tips and notes:
Apart from expressing the immediate past (something that has happened), the -me- tense is also used to express a current state of being, where English would use the present tense. There are some verbs that, grammatically, can use the present -na-, but generally must be used with -me-. These include kuchoka - to be tired (to become tired), kuchelewa - to be late (to have been made late), and kushiba - to be satisfied/full (to have been made satisfied/full).
Nimechoka. (I am tired.)
Amechelewa. (He/She is late.)
Tumeshiba. (We are full.)
Umepotea? (Are you lost?)