Getting silicone gel implant and crescent lift, how long will it take for my scarring to be unnoticeable?

Most likely you can cover the scars with make up and have your breasts exposed in about two weeks. In general scars of crescent lift fade well within 3-5 months after surgery. but this also depends on the extent of the lift and your skin tone/color.

Camouflage make up, lasers, and over-tattooing your scar can all be used for successful hiding of your scars until they fade which can take up to a year. 

The crescent or periareolar mastopexy is ideal for patients with mild ptosis who require lifting the nipple no more than one to two centimeters and little changes in overall breast shape. During this operation, a periareolar incision (i.e. an incision placed at the junction of the breast skin with the darkly pigmented nipple/areola skin) placed at either the superior aspect of the nipple-areolar complex or surrounding the entire nipple-areolar complex is used. Through this incision, the skin envelope covering the breast tissue is reduced and the breast tissue can be reshaped to a small degree. The advantage to this operation is the minimal amount of scarring which is hidden at the border of the breast skin and areola. The main disadvantages of this operation are that it is not powerful enough for patients with large degrees of sagging, poor skin quality, or flaccid breast tissue. Additionally, the incision placed at the junction of the breast skin and pigmented areola may widen with time, cause flattening of the apex of the breast, and cause “pleating” of the skin that may take several months to resolve.