###Human: Cortisone injection for tendinitis is hurting more. Why? ###Assistant: Hello. From the brief history you have given, it seems like there is not much to worry about. First of all, I need to know some more detailed points. Where exactly in the wrist the shot was given? I mean is it the extensors of the thumb (de quervain) or is it for any other finger? Also, do you have thyroid issues? Sometimes when the large volume of fluid is injected into the tendon sheath and surrounding area, due to distension it can cause severe pain and patients do complain of exaggerated symptoms prior to injection. Small vessels must have been punctured (quite normal) which lead to extravasation of blood hence the bruise. It will take a few more days, but both the bruise and the bump should go away. Do apply ice packs there you will get you the necessary relief. Ganglion cysts are notorious for recurrence but highly unlikely to be associated or related to the injection. If you can send me a clinical picture that would be better. Splint is fine but you do need to mobilize your wrist for a very long time otherwise you might end up having stiff wrist (2-3 weeks should not cause any stiffness). Understanding tendinitis is important you need a very specific rehab protocol and few medications and you should feel much better in few weeks time. Did you get your vitamin D levels tested? Kindly revert with the info.