Bruise (Hematoma): This is the most likely diagnosis given the description of a black and blue raised area, which is typical of blood leakage into the tissues following trauma. The pain and tenderness to touch further support this diagnosis.

Insect Bite or Sting: Certain insect bites or stings can cause a raised, painful, and tender area, especially if there is an allergic reaction involved.
Cellulitis: An infection of the skin and subcutaneous tissues that can present with redness, swelling, warmth, and tenderness. While it might not initially appear black and blue, the presence of pain and tenderness could suggest cellulitis, especially if there's a history of trauma or infection.
Eczema or Dermatitis: Certain types of eczema or dermatitis can cause raised, painful, and tender lesions, although they are less likely to present with a black and blue discoloration.

Deep Vein Thrombosis (DVT): Although DVT typically presents with swelling, warmth, and pain in the affected limb, it can sometimes cause discoloration. It's crucial to consider DVT due to its potential for severe complications like pulmonary embolism.
Necrotizing Fasciitis: A severe infection that can cause pain, swelling, and discoloration of the skin. It's a medical emergency that requires prompt treatment.
Compartment Syndrome: A condition resulting from increased pressure within a muscle compartment, which can cause pain, swelling, and sometimes discoloration. It's an emergency that requires immediate intervention.

Kaposi's Sarcoma: A type of cancer that can cause lesions on the skin, which might appear as black and blue raised areas. It's more common in immunocompromised individuals.
Vasculitis: Inflammation of the blood vessels that can cause a variety of skin lesions, including those that are raised and discolored. The presentation can vary widely depending on the specific type of vasculitis.
Lymphoma: Certain types of lymphoma can cause skin lesions, although this would be an uncommon presentation for a black and blue raised area on the thigh.