If you are one of the lucky ones who have already gotten your COVID-19 vaccine, you may have had some soreness in your arm at the injection site. This is completely normal and should go away a few days to a week after you receive your shot. However, if you've had the Moderna COVID-19 vaccine, you may experience what some people refer to as "COVID Arm" where the arm not only swells at the injection site, but recipients have also developed a rash with raised bumps 7 to 10 days later. Doctor's say it's a hypersensitivity to the vaccine or an allergic reaction, but nothing to be concerned with unless you are experiencing other symptoms and/or is last for more than 48 hours .