6 months old fever vaccine

my 6 months old just had his vaccination today. previous time he had a low grade fever but i didnt have a proper thermometer to measure.. this time around im monitoring him more frequently. his body is really warm, but his temperature is always between 36.8-37. but he feels really warm. infact the scanning thermometer showed 35-36 degrees. is this considered fever? should I be concerned about his body heating up?