You may notice a slight redness in the few minutes immediately after the performing the injection. If the redness persists and/or is accompanied by any of the other signs listed below, it is a sign that you should have it evaluated by your physician.Typically, you should not feel any heat under the injection site. If you do notice some warmth that is not constant, and do not have any of the other warning signs, you will want to monitor the site. Make sure to mention it to the doctor if the warmth does not pass.Swelling at the site may feel either soft and mushy, or it may be hard and pea-like. It may be helpful to use a pen to draw along the border. This can help you determine if the swelling is localized or if it&#39;s spreading. Any swelling that continues to spread or does not go away in a few hours should be evaluated.Drainage immediately after the injection is normal. It may simply be the medication leaking out of the needle track. If you notice any drainage that has a color or odor to it, it may indicate the presence of an infection. Make sure to call your doctor immediately.Any time you have a fever greater than 101 that is unrelated to a cold or flu, you should mention it to the doctor. Fever usually indicates an infection and must be evaluated, especially if you have any of the other signs listed here.Some pain is associated with an injection -- that&#39;s natural when you puncture the skin in that way. However, pain that is severe and persistent should be mentioned to the doctor.