This question already has an answer here:
I am a Ghanaian by birth but have Argentine citizenship. In 2015, I first went to Ghana, then went on to France where my passport was stamped.
I spent one month in France, 2 weeks in Germany, 2 weeks in Italy, 2 weeks in Belgium. When I took the bus from Brussels to London, I didn't get an exit stamp. I returned to Argentina from England; my passport was not stamped on exit there either.
I traveled from Argentina to Ghana and on to Turkey, where I am now, and my passport has an entry stamp. I'm planning to take a bus from Turkey to other areas in Europe.
Can I enter the Schengen area without a problem, since I didn't get an exit stamp from any of the Schengen states I visited in 2015 before going to London?