Hi
Prednisolone is a steroid. Steroids have many different effects in the body, some good and some negative. In essence, a steroid injection will suppress the local inflammatory response, to help with pain symptoms. Localised injections of steroid (https://sportsmedinfo.sg/treatment/steroid-injections/) tend not to have the same systemic (body-wide) side effects as oral steroids, which include changes to blood sugar, blood pressure, fat distribution in the body, stretch marks, hair thinning, agitation etc.
By suppressing the immune response, oral steroids can help with many of the body-wide conditions.
BW
Dr Dinesh