Apparatus for facilitating delivery of a substance through skin of a subject, comprising a patch assembly 180 having a first portion 195 and a second portion 197 adjacent to the first portion 195, the first portion 195 being shaped to define an open portion 188 of the patch assembly 180, such that a region of the skin is exposed through the open portion 188 when the first portion 195 is placed on the skin, and the second portion 197 comprising a pad 194 comprising the substance, the pad 194 being adapted to be brought into contact, through the open portion 188, with at least a portion of the region of the skin, the first 195 and second 197 portions being adapted to articulate at respective edges 192 coupling the portions 195, 197.
