Once your HP low, probably you will run away and head base. Sometimes, heading back is not a good option.
When you think you no longer in attack and you think you able to help your team mates, just do so. It may change the whole game.
Get back and help your team. This is your chance to get some kill. Be careful though, your HP is low, even a single blow could kill you. Do this if you sure you can survive or escape if they trying to gank you again.
You can save time and gain more exp and gold. If you can't enter the fight, just stay near to get additional experience from enemy if they got killed.