Perlane lasts about 8-12 months in my experience. It can depend upon how many syringes are injected and if there was residual Perlane in the face pre-injection. The best way to get rid of Perlane, which is made of hyaluronic acid, is to have a doctor inject hyaluronidase in all the Perlane treated areas. It works in about 2-5 days to dissolve the filler. And then your face will return to its normal proportions.
Perlane usually stays for 6-12 months but that depends on the depth it was injected, the amount, and the actual placement of it. It doesn't get thicker or more volumized with time - unless you are excessively pressing on it and trying to move it, in which case you could be building scar tissue there. So keep your hands away from it. You don't have to wait for it to go away, or look like a chimpanzee. Just go to a physician and have some hyaluronidase injected to remove it.
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There is no reason to walk around like a chimp and not be happy with your results. Simply have a physician inject the area with hyaluronidase and this will dissolve the filler very quickly, sometimes before you leave the office.