Epididymitis: This condition, which is an inflammation of the epididymis (a tube at the back of the testicle that stores and carries sperm), is a common cause of testicular pain and swelling, especially after a urinary tract infection (UTI) or a similar condition. The symptoms of epididymitis include pain and swelling in the testicle area, which matches the patient's presentation. The fact that the patient took Cipro (an antibiotic) for a possible UTI and now has sensitivity in the testicle area and a swollen, tender sperm tube (epididymis) supports this diagnosis.

Orchitis: This is an inflammation of one or both testicles, usually caused by bacterial or viral infections. It can present with testicular pain, swelling, and tenderness, similar to what the patient is experiencing. Orchitis can occur alongside epididymitis (epididymo-orchitis) and shares similar risk factors, including recent UTI treatment.
Testicular Torsion: Although less likely given the progression of symptoms, testicular torsion is a condition where the spermatic cord becomes twisted, cutting off the blood supply to the testicle. It typically presents with sudden, severe testicular pain, but the pain can sometimes be more gradual. The patient's worsening condition despite antibiotic treatment could potentially suggest a complication or a different diagnosis like torsion, especially if the pain is severe and acute.
Ingrown Hair or Folliculitis: These are less severe conditions that could cause localized pain, redness, and swelling in the groin area, including the inner thigh. However, they would not typically cause significant swelling and tenderness of the sperm tube.

Testicular Cancer: Although rare and less likely to present with acute pain and swelling, testicular cancer can cause a testicular mass or swelling. It's crucial to examine the testicles for any masses and to consider ultrasound evaluation if the diagnosis is unclear or if symptoms persist.
Necrotizing Fasciitis: A severe, life-threatening infection of the skin and subcutaneous tissues. It's rare but can occur in the genital area (Fournier's gangrene) and presents with severe pain, swelling, and skin necrosis. The patient's worsening condition despite antibiotic treatment could raise concerns for a more aggressive infection.

Henoch-Schönlein Purpura (HSP): A form of vasculitis that affects blood vessels and can cause a variety of symptoms, including skin rash, joint pain, and abdominal pain. It can also cause testicular pain and swelling, although this is less common.
Spermatocele or Epididymal Cyst: These are benign cysts that can form in the epididymis and can cause swelling and discomfort in the testicle area. However, they typically do not cause acute pain or significant tenderness.