Your statement looks fine to me, although I have corrected a few unrelated grammatical errors because it helps to make the question clearer. :)
Although in this case is suggesting that an exception to a rule has been made. Here, the implied rule is that a graph representation is expected to be a complete one. It's perfectly reasonable to use because in the clause that explains why the exception has been made. Here's another example, using the recent Kentucky Derby result:
Although California Chrome won without a particularly fast time, this was because Espinoza eased him up at the end to save him for the Preakness.
The "rule" is that you want to run at a time comparable to the other great horses. The exception is that he was running fast enough to win and had another race to run soon.
At first none of the examples sounded good to my ear, but after I looked it up it seems that the 2nd and the 3rd are correct.
Many discuss the topic that whether medicine has true benefit on our society.
Whether is a subordinating conjunction. That is also a conjunction. Pilling up conjunctions one after another does not serve a purpose, and it is grammatically incorrect. Both of these conjunctions can be used to introduce a noun clause, but in your example the noun clause is derived form a yes/no question:
Does medicine have true benefit on our society?
Therefore you should use whether (that is used for noun clauses derived from statements).
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Many discuss the topic of whether medicine has true benefit on our society.
Google books shows evidence of "... of whether..." construction usage, e.g. in: "...the question of whether the pure self can be conceived of in unity with a living organism." At the same time
LDOCE gives examples of the construction "topic of". Since these two were my main concerns, the sentence should be correct.
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Many discuss the topic on whether medicine has true benefit on our society.
Again, there is evidence of usage of the phrase:
topic on whether, although there are only 68 hits, which would indicate that this phrase is used rarely.
Finally, Many question whether medicine brings a true benefit to the society would be my personal preference, but there are many ways to phrase this thought.
Best Answer
The preposition phrase in spite of requires that a noun phrase of some kind must follow it - you can't just put a sentence there.
The correct phrasing is:
The noun phrase taking prescribed medicine regularly refers to the act, and the person doing it, which was previously I, is now provided by the second part of the sentence, my health hasn't improved.