I am 66 yo male, 6'3", 280lbs in usual good health. I have been running an elevated temp for 3 days using tylenol to lower temp. Morning temp is around 99 but even with tylenol temp spikes to 102 in the evening. Only other symptoms are occasional chills and 2 nights ago woke soaking wet from night sweat.

Do I need to be concerned?

It's a good idea that you get yourself to a quick care or in to your physician as soon as possible. I would suggest the quick care, especially due to your age, and the fact that you're experiencing temp spikes as high as 102. Adults cannot stand temps that high, and to that effect, the older we get, the less our bodies are able to "bounce back" like children. Your safest bet would be to accept that you have likely done the best you can for yourself at home, and now is the time to seek professional medical help. If your temp. Climbs higher than 102, you need to consider this an emergency and proceed immediately to the emergency room. If you live alone, please have a friend or neighbor drive you.