You would have to complete at least some undergrad classes in the US in addition to MCAT in order to apply to med school here. There are schools that do not require UG prepreqs completed in the US but there are VERY few and VERY hard to get into (i.e. WashU or Harvard). Best recommendation to you is to work on getting your medical degree in the Philippines and studying for the USMLE at the same time and then just take the Step exams. If you get a good grade, there would not be too much trouble getting into a residency in the US... it probably wont be a dermo residency (of course depends on your USMLE score, if they are through the roof, the sky is the limit), but you probably will get into a residency program. In addition, many US med schools (i.e. Hopkins, WashU, NYMC, and others) require 100% prepayment of medical school tuition + living expenses (about $220,000-240,000) upfront payment.