First thing is to read this article
Here are my thoughts:
1) with a resting lactate of 2.0 I wonder if you had eaten not long before the test? High carb snack maybe?
2)The drop to 1mMol/L after just 5 min is a good sign that that your aerobic system was beginning to come on line. Lactate was being taken up by the ST fibers and used for fuel faster than lactate was being produced.
3) It could have been the heat but it might also be that you were not well warmed up before you started increasing the HR. Your ST fibers were warmed up enough (aerobically awakened) to handle the lactate at 117 but not quite ready for the lactate being produced at 126. Try a longer warm up.
4) I doubt it was a bad reading. When they are bad they are crazy high or low or you get and error reading.
5) If you can use the same poke and still get blood out of it 3-5 min later then yes you can use the same hole. Most people will clot in that time and need a new poke. Squeezing hard on your finger can mess up the reading.
I hope this helps.