Not to your face. They'll say it looks terific. Some wigs need to be positioned lower on the forehead than others. I had to wear a full inch lower than the other. Experiment in a mirror.
Most wigs have adjustment tabs inside near the ears.
You can wash a synthetic wig with wig shampoo. Just soak it in cold water and shampoo. Then soak it in cold rinse water. At this point it will look like a wet terrier. 2-litre Coke bottle to dry.