ethics - What can I do if one of my referees falsifies information in a Letter of Recommendation?

I am in a difficult situation in regards to letters of recommendation and I would like to ask for a bit of advice from all of you.

This past June, I applied to several different medical schools across the country and each one required me to submit at least 3 letters of recommendations (1 from a non-science professor and 2 from science professors). All of the faculty members that I asked were happy to write me letters of recommendation. However, one of the faculty members delayed writing the letter of recommendation for a very long time (almost 5 months) despite several reminders. One of the medical schools had a strict deadline by which they wanted their application to be completed and because of the delay from this one letter writer, I was automatically rejected from the school. At this point, I decided to return to my university (I already graduated) and speak with my letter writer in person.

From the discussion with my letter writer, I found out some very disturbing things about his intentions. He was very displeased with my in-person visit to his office (even though I did email him several times beforehand without him bothering to respond). It was at this point that he began accusing me of things that were 100% false and was threatening to include this false information in his letter of recommendation. He eventually submitted his letter of recommendation, and, at this point, I could not stop him from doing so.

Now I know that many of you will say that I should have been able to see this coming and avoid asking this faculty member for a letter of recommendation. But, with all honesty, I was completely under the impression that this professor will write me a strong letter of evaluation. I viewed this person as someone that was a true mentor to me throughout college, and this situation is very disheartening. In my honest evaluation of the situation, I believe that writing a negative letter of recommendation that includes false information about a student out of spite is completely unethical. I also believe that I should have the opportunity to defend myself.

There is no way that I can see what he wrote in his letter of recommendation. If anybody here has any sort advice in regards to this situation, please I would greatly appreciate it. I would hate to see a letter of recommendation that contains false information ruin my chances of pursuing my academic goals. Is it possible to take legal action in this matter?