The movement of the lip is not then a source of danger in displacing the mass, since the acute swelling of the lip tissue prevents its free movement for several days, which gives the injected mass an opportunity to establish itself and find its proper place.
Another advantage in using this preparation subcutaneously is that it is less irritating than hard paraffin, permits freer movement, and creates a better production of new connective tissue.
While a part of the mass may be absorbed during the replacement period the lip retains its normal consistency, and if the desired contour has not been attained a subsequent injection may be made in three weeks’ time without interfering in any way with the former result.
The only precaution, aside from avoiding the injection of blood vessels, is to keep the injection from the prolabium or vermilion border. The latter tissue is very prone to fatty degeneration or to yellowish discolorations when such a foreign mass has been introduced into or near its structure.
There is no objection in injecting the lip, upper or lower, in several places, as the cellular network about the mouth is sufficiently dense to prevent the escape of the vaselin injected from the adjacent opening if the distance is not less than a half inch between the punctures.
The injections may be made from above downward in the upper lip and, vice versa, in the lower. They should be begun at the outer angle working toward the median line.
The reaction following such an injection is usually more severe than in any other tissue of the face, owing to the great number of fine blood vessels, but the swelling is readily controlled in two or three days by cold applications.
Aristol collodion dressings over each wound suffice to close the punctures.
In the median variety of defect, where a cicatricial band separates the lip into halves, it may be found necessary to do a subcutaneous dissection before a suitable injection can be done, but in cases of long standing the dividing wall is exceedingly thin and the threadlike adhesions below are quite easily broken up by the force of the injection. The later product of new connective tissue will tend to further improve the contour.