UVB ultraviolet lamps do have the potential to cause some harm, especially if used improperly. Ultraviolet (UV) radiation can be divided into three main components: UVA, UVB, and UVC. The UVB spectrum primarily involves light with wavelengths between 280 and 315 nanometers, where UVB lamps used for therapeutic purposes typically use either Narrow-Band UVB (NB-UVB), at a wavelength of around 311 nanometers, or a specific wavelength of 308 nanometers. 

1. Skin Burns: Similar to sunburn, overexposure to UVB light can cause redness, swelling, pain and even blister formation. This damage is usually temporary, but if it occurs frequently, it can lead to long-term skin problems.

2. Accelerated skin aging: Long-term exposure to UVB can lead to decreased skin elasticity, increased wrinkles, and skin thinning. 

3. Increased Skin Cancer Risk: Although the risk from narrow band UVB therapy is relatively low, any form of UV exposure has been linked to the development of skin cancer. Prolonged or frequent UVB exposure may increase the risk of developing basal cell carcinoma, squamous cell carcinoma or melanoma.

4. Eye Injuries: Keratitis or other eye problems may result from looking directly into a UVB lamp or prolonged exposure to UVB light without proper protection. Protective eyewear should be worn when using UVB lamps.  

5. Immunosuppression: Prolonged UVB exposure may suppress the skin's immune function, making it more susceptible to infection. If you are considering treatment with UVB lamps, it is strongly recommended that you consult a medical professional and follow medical advice to minimize potential risks.