You could try to reach Concourse F (and report back to us, please!); as I said, I am not 100% sure if it is isolated or connected to Concourse E.
(Concourse F is the only one I have never used at MIA)
Concourse E is not connected to F. The OP can try to get through Security for the lounge but I would not count on it. There are two AA Admirals Clubs in Concourse D (which is connected to E) which offer daily passes at $50. Both have showers although both are very crowded.