The question is flawed since methane doesn't lose electrons directly.
When methane undergoes a combustion reaction, it breaks apart and is no longer methane. Atoms are rearranged and electrons go where they are needed to make new bonds. More on that later.
To "lose 8 electrons" sounds more like the action of a battery where one part of the battery will lose electrons that flow outside the battery, through some device, and into a different part of the battery. Methane does't do this in a combustion reaction. If you are talking about using methane in a fuel cell, I don't think it should be called a combustion reaction.
In chemistry, a combustion reaction is one with a hydrocarbon (a compound with hydrogen and carbon, like methane) and oxygen. In most cases we would be saying the hydrocarbon is burning.
I am attaching a picture showing where the electrons are before and after the reaction. You will see that even though the electrons for each element are really the same as each other, the number of outer electrons (valence electrons) associated with each element doesn't change before and after the reaction. Methane didn't lose electrons since methane broke apart and electrons could be thought of as staying with the atoms that own them.