What are ridges under the skin?

Ridges under the skin can refer to various conditions, including skin conditions like lichen planus or dermatofibromas, which may cause raised areas or lines on the skin's surface. These ridges can also be a result of scar tissue formation from injuries or surgeries. In some cases, they may indicate underlying issues such as poor circulation or connective tissue disorders. It's important to consult a healthcare professional for an accurate diagnosis and appropriate treatment.