It is surprising how quickly your past disappears at work. You might get a passing enquiry in your first weeks of residency as to where you went to med school, but on the whole no-one cares, and this will become more and more true as time goes on. What people care about at work is that you turn up on time and don't leave early, that you do your best to do what is expected of you and a bit more, and that you are an easy person to get on with.
It is a good idea to ask your "stupid" questions early on - by which I mean, if there is anything about how your organisation works, or who people are, or where you get logged in/supplies/admin help/call a code/use the records system and so on, you have a free pass to ask them early on. Don't be the person who is too embarrassed to ask and then is slightly at sea for ever more.
If it's about medical knowledge, be prepared to admit ignorance rather than bluffing. If you get the reaction "you should have known that", try reading around the subject and then going back to the person who had that reaction, showing that you have since read up about it, and perhaps asking them an intelligent follow-up question. This will demonstrate that you have remedied your lack of knowledge, that you have studied in your own time to do so, that you have put your new knowledge in context and that you have moved on to the next level.
Good luck.