In some ways you are very lucky because your experience of high school, hobbies and life experience will already be different from many UK/ home students so you should take advantage of this in your personal statement. But you also need to make 2 things very clear. Firstly, why do you want to study in the UK and secondly, you need to show that your English is of a good standard (usually IELTS 6ǌ or above). It is no good having IELTS 6Ǒ if you personal statement is full of grammar and spelling mistakes. But DO NOT pay for someone to write your personal statement for you on one of the many websites offering this service. If you have IELTS 6Ǒ, you do not have perfect native speaker style English and universities may reject your application if they suspect it is not your writing.
The reader of your medical school application is expecting a degree of proof and really wants to know how you know. It's not enough for you to say you want to help people. How do you know what you want to do in medicine, what have you done that leads you to know that? How to write your medical school personal statement: Persuasion The most persuasive way to answer this question is by sharing experiential knowledge. You would say to an admissions official in conversation, "I know because I've done it. That's how I know. And I can give a specific story."