First, a word of caution. Tread lightly. You are wading into some highly litigious waters. I don't say that to dissuade you. But rather to let you know in clear, unambiguous language that pharma and cosmetics manufacturers are generally militant about enforcing their patent rights against would be competitors. I know this first hand, as a former client of mine (responsible for ~30% of my 400+ case docket at my old firm) was a large cosmetics manufacturer who significantly invested in the development of therapeutic ointments. It was not at all uncommon for them to ask one of our attorneys to buy all the topical ointments sold, e.g., at a CVS or Rite Aid, compare the ingredients to what was disclosed in some of their applications (which had priority dates stretching back 10+ years), and to write new applications with claims that read, verbatim, on the ingredients identified on the packaging of a competitors product. The implications of that practice are obvious. And if a cosmetics/pharma company is willing to pay a lawyer $350/hour to go to CVS and then create IP based on what he found, it will have no qualms crushing a would be competitor who might be infringing the existing claims of one of its patents.
But all that said, DogDay's advice is good. You may well be able to obtain use or treatment claims in this instance. "Topical" application does not necessarily imply, e.g., "treatment of scar tissue," or "treatment of acne scarring," or "use of a composition comprising X for the treatment of scar tissue." Given the right facts, it is possible that a case could be made that such a use or treatment is novel and non-obvious in view of the prior art. Considerations such as dosage, manner of application, side effects, etc. all come into play.
I also second DogDay's suggestion that you have some protection (read, IP) in place before contacting the pharma company. An ounce of prevention . . . as they say.