Upvote:1
There are a couple of possible scenarios:
Your visa expires on February 25th but you haven't used up your 90 days. You can either extend your visa or get a new one to come back to the Schengen area but you will probably need to return to Nigeria for that as visa extensions are only intended for βserious personal reasonsβ.
Come February 25th, you will have stayed 90 days in the Schengen area. You will not be able to get another Schengen short stay visa, even if you go back to Nigeria to apply for it. You need to leave as soon as possible to avoid falling foul of the maximum stay rules or secure another type of visa from the Swiss authorities.
See also How does the Schengen 90/180 rule work?, Can I extend my 30 days Schengen visa in Switzerland? and Is it possible to extend a tourist Schengen visa (12 more days)?