A liquid delivery wand includes a centrally located fluid storage chamber. An absorbent pad is located within the working end of the wand for applying the treatment liquid to the skin while a vacuum is applied to the skin through an abrasive coated treatment tip. Coaxial, cylindrical tubes with flow channels between tube surfaces control the flow rate, the pressure drop being established by the close fit and length of adjacent surfaces of the coaxial components. The flow rate of the liquid is adjustable by simply rotating the interfitting components. The chamber that holds the liquid is sealed from the atmosphere at the distal and proximal end. When the wand is connected to vacuum and the distal end contacts the skin, the vacuum applies a negative pressure to the fluids within a fluid chamber. A small portion of liquid is thus transferred to wet the filter pad.