youre 5 5' and he's 6 1'? Man, do you have to jump in order to punch him? haha!
You dont actually have to fully focus on your opponents face to hit him there. I like to use perhifal (spelled wrong:( ) vision. Focus on his chest bone and monitor his movements. But your head may be exposed with that hieght disadvantage. I know the best way to get in on a man with a longer reach and thats by getting in close and throw short jabs and hooks. So, I would say, work his body, in close and don't worry about head shots from a distance. Once you crowd him, he will hunch over to block your body shots, thats your time to mix it up and go head hunting.
"Kill the body and the head will die"
Phases ®