The influence of an interface on the energy level structure of hidden quantum dots was studied. A self-consistent formalism was used for the calculation of the linear response of a single hidden quantum dot and a dilute layer of quantum dots in the presence of a static homogenous magnetic field. The article studies how the shifts of energy levels caused by self-field interactions (the so-called Lamb shifts) depend on the distance to the surface and magnetic field. Numerical calculations show that the interaction between the quantum dot and the surface leads to substantial Lamb shifts. These shifts can reach relative values of more than 10%, and strongly decrease if the distance between the quantum dot and the surface increases. The influence of a concentration of quantum dots in a hidden layer was studied, and absorption spectra were calculated. The numerical calculations show that the influence of interaction between the quantum dots inside a dilute layer on the absorption profile is rather weak.