The ornamental design for a displayunit for skincare device, as shown and described.
1. Display unit for skin care device
1.1 : Perspective
1.2 : Front
1.3 : Back
1.4 : Left
1.5 : Right
1.6 : Top
1.7 : Bottom
1.8 : Reference
The broken lines show portions of the article that form no part of the claimed design. Reference view 1.8 shows the claimed design with its translucent sliding door partially open to reveal a skin care device in it.