With the recent reopening of U.S. relations with Cuba, what have they been up to since the embargo?

This is a really broad, broad question. I´ll take it as "what truth is there to the assertions Cuba makes about itself abroad in medicine, etc."

For one thing, Cuba has socialized medicine. It is free to all citizens. You do pay for medications, but they are ridiculously subsidized (20 cents in moneda nacional, or less than 5 cents in US dollars is what I personally paid on several occasions). If you don´t have enough for even subsidized prices there is a form you can fill out, at which point you are exempted from any charges for your medication. My ex-girlfriend´s mother got cancer and all her chemo, the hospital trips via ambulance, etc, were all covered by the state. Mind you, the system isn´t perfect. Doctors are extremely overworked and underpaid, having to rely on "gifts" from patients, which are increasingly obligatory, in order to live a dignified life. Cuban policy of sending medical professionals abroad in exchange for oil or money sent to Cuba (which in turn helps support social policies, etc.) has also caused Cuba to have less doctors than it used to, causing extra strain on the system. All in all though, if I were a poor man who got sick I´d rather be in Cuba than the US. If I were a rich man who expected the best care in the world and could pay for it, I´d still prefer the US, but Cuba has some pretty amazing doctors.

Cuba did send troops to fight in Africa. Contrary to what you understood, they sent them mostly to Angola (South Africa was under the anti-Communist apartheid government until the early 1990s). After the Portuguese left Angola the country was destabilized by civil war and the incursion of racist South Africa into Namibia, which is the country between South Africa and Angola. White South African soldiers even invaded Angola directly. At this point Cuba also intervened with in excess of 20,000 Cuban soldiers (not to mention other specialists such as doctors) who helped defend the leftist Angolan government from the late 1970s until a little before the fall of the USSR. Nelson Mandela was very vocal in saying that Cuba fighting South Africa was a huge contribution to ending the apartheid regime, both in symbolic terms ("ending the myth of white invincibility") and concrete ones (by exhausting South African resources in a war of attrition abroad while black South Africans fought to end Apartheid at home). Here is a brief article on it from Democracy Now:

http://www.democracynow.org/2013/12/11/the_secret_history_of_how_cuba

You can also read more on the subject in Piero Gleijeses´ book on Cuban participation in Angola, called Conflicting Missions.

Cuba, after the Revolution, also effectively eliminated illiteracy with massive national literacy drives, built up a biomedical infrastructure that allows them to do their own research and even export their own brands of medicine, made higher education accessible for all by making it free, they allowed Cuban farmers to till their land without being exploited by huge landowners anymore, served as a safe place of exile for leftists around the world whose governments made it unsafe to stay at home (as frequently happened in Latin America in the 60s, 70s, and 80s), has a huge influence in poor Latin American countries thanks to medical and education professionals who frequently offer services free of charge to local populations (their government foots a modest bill), among many other things.

Cuba still has some major issues, of course. Cuba isn´t really democratic in any sense of the word. They have issues with censorship. They nationalized most of their economy after 1968, which was disastrous, so much of the economy doesn´t really work (they are now slowly privatizing parts of it again). It´s not perfect, but it is still a lot better than China in terms of human rights abuses, and many of its issues are compounded by a siege mentality due to the fact that we spend millions of dollars a year OFFICIALLY on "regime change" (i.e. we undermine moderate forces in Cuban politics by actively paying critics of the regime, which makes them all look to many Cubans as US paid puppets).

Under Raul Cuba has done away with a lot of the worst of the worst of its old policies and will hopefully continue on the path towards a more social democratic, and less sovietized, system.