Treatment of the upper face is, usually, an almost pain free procedure. The needles used are very small and with good technique it is almost always possible to avoid causing bruising.
The most common side effect from filler injections are headaches. These can affect up to 1 in 10 people. For most people it settles down within a day or two, however in some people it can take up to a couple of weeks and I have seen one or two patients who have found the headaches lasted the whole three month duration of the treatment. For most people however the headaches are very mild, self limiting and it is unusual to require any type of pain killer for them.
Complications from this treatment can occur by the toxin spreading to near by muscles that were not intended to be targeted by the treatment. In the upper face this can cause temporary drooping of the eyelid or eyebrow. Because this usually happens as a result of a small amount of toxin spreading to the wrong area, rather than a direct injection into the wrong area, it tends to wear of quite quickly – usually within a couple of weeks. In the lower face and neck, it is possible for the toxin to diffuse into muscles which help to move the mouth resulting in a lop sided smile. Rarely, toxin treatment in the neck can affect speech and ability to swallow.