You can only get four chests through wins each week and the limit will reset once the week is over, but if you get a chest with a specific champion then you can no longer do it with that champion until the season resets. The other way you can get chests is to buy them from the League of Legends client store. One chest will cost 125 Riot Points but has bundles ranging from almost 200 RP to nearly 2,000 RP. You can buy up to 25 chests a day and this will not be counted towards your weekly limit.
A high fever is when the body temperature rises above 103 degrees Fahrenheit in an adult (or above 101 degrees Fahrenheit in a child).
Hypoglycemia/ low blood sugar would be considered blood sugar levels less than about 70. Your result of 103 is normal, not hypoglycemia. It is likely that your symptoms may be from other causes.