If you were going into hospital to have a major operation, you would like to know the surgeon was properly trained and had lots of experience doing that particular operation, wouldn’t you? The same applies for Botox injections. Unless you have a properly trained and experienced doctor do the job, you cannot be sure it will be done properly.
In fact, even among trained and qualified doctors who’ve done a lot of work on wrinkles in this way, the application can vary. For instance, suppose you were having those crow’s feet at the corners of your eyes treated. Once doctor may give mini injections into each of the several wrinkles that form when you smile while another may consider just one larger injection sufficient to treat them all. Neither technique is necessarily wrong – sometimes what works on one person simply doesn’t work on another.