As provided in the attached 13-page manuscript by authors Singh. Wang. Yee. and Larin, we provide the methods and system for providing depth-resolved real-time visual feedback to a physician during cosmetic dermal filler injections with micrometer spatial resolution using a noninvasive elastography system. Also included is a method for assessing the elasticity of the tissue before and after the injection to evaluate the efficacy of the injection. The elasticity assessment method utilizes a focused air-pulse to induce a micrometer scale displacement in the skin and the optical coherence tomography system to image this displacement. By utilizing a model-based reconstruction method, the viscoelasticity of the tissue at a specific measurement position is obtained from the temporal deformation profile. By comparing the viscoelasticity before and after the injection. the physician can determine whether further treatment is necessary. The skin can also be evaluated over an extended period of time to determine the necessity for follow-up treatments. A combined focused air-pulse delivery device and optical coherence tomography/elastography system is disclosed.