These days, certain doctors and professors state that tongue thrusting can lead to undesirable facial bone remodelling in adults. i tongue thrusted very hard downwards five times when swallowing drink, will this have caused any downward growth?

One time event ?: If you did this one time only -- no chance of a problem. If it is a frequently recurring habit, then you might have a problem over time. Most likely you will not alter your facial bones as such, but rather your alveolar processes supporting your teeth resulting in tooth movement which will change your facial appearance. See the Orthodontist for help if this is a habit. Good Luck.