Initial evaluation should determine whether this is a static or a dynamic cause. The severity of the furrow should be assessed. Most commonly these represent themselves as "# 11" between the eyes and they are usually vertically or slightly obliquely oriented. Sometimes you could have a horizontal furrow as well. Some individuals may have a single, very deep furrow. Initial therapy usually includes a trial of botulinum toxin with or without a filler. Caution must be exercised when injecting any filler in this area as it is prone to skin slough or necrosis due to an embolization of a blood vessel. In addition you can have a "doughnut" effect, i.e, the filler can preferentially lay around the furrow, thus accentuating it more. If it were me, I would only have a physician perform an injection. There are more invasive but less risky options available as well for deeper wrinkles and furrows. One option is an autologous fat transfer. Small amount of fat is harvested from a thigh, processed and then injected with a blunt cannula under the furrow, this works very well. In addition, one can perform sub-scission, a technique where the dermal attachments are lysed away from the underlying muscle to release the furrow. The space could be filled with a filler in a much safer and more predictable manner or filled with fat. Finally, if none of the above options have worked, a severely deep furrow could be excised, or cut out and then sutured in a very precise way such that the scar could be imperceptible, certainly less noticeable then the deep furrow. Bottom line, although a quick filler injection could be done, it is not risk free.