This would not be a serious article if we were not Africans. It is really difficult living in the times we are in right now. Most people have been exposed to western culture either through the media or travels and experiences.
Nigerians are the most travelled people in the world. I have uncles who joke that if you travel to a strange land and there is no single Nigerian you should leave that place because it must be a bad land. Jokes aside what I am trying to say that if you have people who have been around as much as we have then there is definitely a mix of cultures. However, I have noticed some way of thinking stays true to us.
Africans and Middle Eastern cultures believe that women should be covered up as a sign of dignity and respect. The western world believes in freedom of expression and liberalism that includes showing as much skin as one desires. Do you know there is even a ban on women been covered up at beaches in Cannes?
After you have been round the world, frolicked with stars become even a sort of celebrity yourself, how much skin is too much at the beach?
I have to burst your bubble here and tell you Bar Beach is not the same as a beach in the Bahamas.  If you wear a bikini here you would be the centre of attention. You would also most likely stick out like a sore thumb. This applies to Alpha Beach, Elegushi and Oniru Beach in Lagos, in fact any public beach in Nigeria.

There is a loop hole here, wait for it. Now, If you wanted to wear a bikini to Inagbe Resort or Ilashe, La Campaigne Tropicana and other private beaches in Lagos and around Nigeria, I say bring your A game because you will have a run for your money competing with the hotties around you.
To answer the question, “How much skin is too much?” It depends on your environment and how bold and confident you are. When in Rome be like the Romans.
There are some benefits of being covered up at the beach;

Preventing sunburns
No Abrasions

Some people go to the beach to really let loose, run around play with the children, ride horses even swim so there are less chances of getting cuts and scratches if your skin is well protected

You may be more care free

You may have more fun if you are less conscious how your belly looks in that suit

No wardrobe malfunctions

I mean what would you do if your bikini top slips off with a bunch of onlookers ogling you?