I'm sorry to hear that the injection site is red and very painful. This could indicate an injection site reaction or possibly an infection, which needs prompt attention.

Here are some steps you can take immediately:

• Avoid touching or pressing the area to prevent further irritation.
• Apply a cold compress gently to reduce pain and swelling, but do not apply ice directly on the skin.
• Keep the area clean and dry.
• Monitor for other symptoms such as increasing redness, warmth, swelling, pus, fever, or spreading pain.

Since redness and severe pain after an injection can be signs of infection or inflammation requiring medical treatment, it is important to consult an orthopedic surgeon or a doctor promptly. They can examine the site, possibly prescribe antibiotics or other treatments, and ensure proper healing of your leg fracture and injection site.

If you experience fever, spreading redness, or worsening pain, seek emergency medical care immediately.

Please do not delay in getting professional evaluation to prevent complications.To narrow down potential causes, we will need some more information.I understand that you had a leg fracture and received an injection in your hip for pain relief, but the area is red and very painful. To help me understand the situation better, please tell me your age and gender.