If your doctor's treatment pattern included the lower eyelid and this was done too deeply, it is possible for the BOTOX to affect the muscles of the face that control the smile. These muscles include the zygomaticus major, minor, and the lip elevators. The swollen nose effect occurs when the levator labii alaeque nasi muscle which lies along the side of the nose and serves as a minor lip elevator gets too much treatment. This muscle is sometimes intentionally injected to treat the so-called gummy smile.
When BOTOX helps our appearance, feedback from the treated muscles favorably affects brain chemistry. Functional MRI studies of the brain have shown that BOTOX used to reduce the pinch at the eyebrow has a favorable effect on mood centers in the brain. Anecdotally, I have seen patients who received unintentional treatment to the muscles that are responsible for mouth movement and smile. The problem is not just that the smile is asymmetric or weak but these treatments also have a profound adverse effect on mood. The effect on appearance may or may not be dramatic but the effect on mood can be disabling and lead to depression. So don't let anyone minimize the significance of this complication.
Now the good news. The BOTOX effect will wear off but it can take months. Your doctor may be very open about the problem in which case he or she can follow you closely or they can be very defensive about the result in which case you may need to find a new doctor. If you become depressed or feel withdrawn recognize that this is the central (i.e. brain) effect of your BOTOX treatment causing action on the wrong muscle groups. This will wear off eventually but it is possible to be so dysphoric that it affects your ability to function socially. If this is the case, it is worthwhile to seek the support of a psychotherapist to help work with you until these symptoms resolve.