Insurance companies are criminals and sociopaths. Do NOT deal with them without a lawyer or you are in big trouble. You need a lawyer yesterday. This is like trying be your own doctor. A very bad idea.
My standard disclaimer: I am not offering legal advice or services, assume all of my advice is completely incorrect, assume I do not know the law in your state and assume that I am just making suggestions for starting points for when you do speak with an attorney. Do NOT rely on anything I write and contact a lawyer in your area immediately after reading my posting.
As I am licensed to practice in Florida and Vermont, I cannot comment specifically on Indiana law, however, generally the short answer to your question is -- Yes, consult a personal injury attorney in your area. You may also wish to review some of the Legal Guides which I have published on A v v o.com, one of which deals specifically with pre-existing conditions.
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