I am traveling to Germany on May 1st for an exhibition for which I have already obtained a visa and its validity is up to May 13th. I am returning on May 12th and then traveling on May 17th to UK, and from UK to Switzerland for vacation with family. As time is very short for applying for a Schengen visa again after returning on the 12th with May 13-14 being a Saturday and Sunday, can I apply for Schengen visa again and can I get 2 valid Schengen visa?
CAN I APPLY FOR SCHENGEN VISA AGAIN AND CAN I GET 2 VALID SCHENGEN VISA?
You cannot have two visas which are valid on the same date.
Your visa will expire on 13 April, and so you will need a new visa to travel on 17 April.
Because the new visa will start on 17 April, i.e. after the old one has expired, you can (and should) apply for the new visa now, before going on your first trip to Germany