if a friend claims possesion of a drug in court when you are both facing the possesion charge will your charge be dropped?

There is no clear-cut answer.  First, in Florida it is possible for two or more persons to be charged and convicted of possession of the same illegal drugs -- i.e., Florida law covers "joint", as well as "constructive" possession.   It is possible to get convicted under Florida law even if the drugs were not physically located on the person/s charged.  However, the state must have some way to show who possessed, owned, or controlled the drugs.  It is not necessary for the state to have direct evidence to show proof of possession, ownership or control.  The State may show proof by "circumstantial" evidence.  Also, it is not necessary to be the owner, be in "actual" possession, and be in control of the illegal substance.  The State may show any of these forms -- including the use of "constructive" possession.   It is possible, under some set of circumstances, that the state may not be able to develop sufficient proof against any of the persons charged.  There is no Florida statute of which I am aware that automatically, by statute or operation of law, increases an individual's potential maximum penalty merely because he/she admitted or confessed to being the owner, possessor, and person in control of the illicit substance -- and claimed the other person had no knowledge or possession of it.  However, that does not mean that the state (if it thought a defendant were lying about the other person's involvement -- but just couldn't prove it) would not take that into consideration in any plea offer -- or that the judge would not take that into consideration in deciding what legal sentence to impose.  Also, a person who is caught lying (even about another person's involvement), under certain circumstances, could be charged with perjury.