If you stay you potentially let the enemy team get a double kill (that's why you wanted to back in the first place) or do you recall and let the tower fall? In the double kill scenario, remember the enemy can just take the tower after potentially too for first tower blood
If the towers gonna die regardless of you being there or not since you can let freeze it just back off, if you give the enemy carry turret first blood and kill first blood you're gonna get wrecked mid game.
There are so many variables to make a straight forward answer. If you were a tank support such as Leona and stayed under turret on your own, then you could let them dive for an attempt for them to kill you, although a simple q and exhaust while tower shoots them down would help give yourself a kill. However, if you were by yourself at bot and 3 champs (enemy jungler shows up) decide they want to dive, it would be best to recall. If the tower is very low on health (less than 40% health), then it would be wiser just to recall.
