A little bit of fatigue; This is a spontaneous report received from a contactable reporter(s) (Consumer or other non HCP).  A male patient received BNT162b2 (BNT162B2), as dose 4 (booster), single (Lot number: FJ4991) for covid-19 immunisation. The patient's relevant medical history and concomitant medications were not reported. Vaccination history included: Covid-19 vaccine (Dose 3 booster, Unknown manufacturer), for Covid-19 Immunization; Covid-19 vaccine (Primary immunization series complete, Unknown manufacturer), for Covid-19 Immunization. The following information was reported: FATIGUE (non-serious), outcome "unknown", described as "A little bit of fatigue".  Additional information: "Reporter stated, "I reside in (withheld) and my pharmacist advised me to give you a call because you are still collecting data regarding the second booster and I wanted to let you know that after the booster shot and I am not sure if this was a true side effect or this was from something else but I had extreme swelling inside my upper and lower lip, similar to Canker sores but not truly a Canker sore because I have been rinsing with a rinse that she suggested and they are subsiding a lot more quickly than they ever have, you know when I was younger. I received this vaccine on Tuesday and by Wednesday evening I started to feel like a swelling inside my mouth and cheeks and around and under my tongue and it is so similar to Canker sores and my pharmacist said that I should call you to report it just for your data collecting evidence." When paraphrased the concern: Reporter stated, "Yes, that is correct, and it still exists today which is now Saturday. Again, I do not know if it is truly related. I normally take a drug for acid reflux but because I am going for endoscopy this coming Thursday, I am off Omeprazole and my doctor put me on Pepcid, just to kind of calm some of the acid reflux. So, I do not know if the sores have anything to do with, you know more acidity in my mouth or not or if it was a true reaction. But my pharmacist said that I should report it anyway because if you received any other call that have the same side effects then it would be helpful to know that I had a similar side effect." When informed the role of Pfizer Drug Safety and about Pfizer Medical Information Department for the questions: Reporter stated, "She gave me the whole print out and because I had the other vaccines, I have a list of all the side effects but she said you were still collecting data for the second booster. This occurred after the second booster, I know what all the other side effects are but I only experienced a little bit of fatigue but nothing like the initial vaccine." When again informed the role of Pfizer Drug Safety and for the questions contact details can be provided: Reporter stated, "Do you want me to call them and report this again or will you, it has been reported?" When asked for permission for further probing: Reporter stated, "No, I do not have the time right now but I just wanted to give you a call to let you know what I experienced." Reporter stated, "My husband had the vaccine, the same, we got at the same time and he did not have any side effects except for, you know a little bit of fatigue but he did not have any sore in his mouth or anything." Reporter was unwilling to complete the report. Thus, further probing could not be done and product details and pharmacy details were unknown. Limited information available over the call".  No follow-up attempts are possible. No further information is expected.