Can the protection from evil and good spell be used on the caster?
It doesn't say anything about it in the descripton but I know that some spells prevent them from being used on the spellcaster.
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The Players Handbook states under the heading Range (PHB 202, emphasis mine):
The target of a spell must be within the spell’s range. For a spell like magic missile, the target is a creature. For a spell like fireball, the target is the point in space where the ball of fire erupts.
Most spells have ranges expressed in feet. Some spells can target only a creature (including you) that you touch.
As indicated here in the description of Range, a spell with the range of Touch can be cast on yourself. Protection from Evil and Good has a range of Touch so the spellcaster can cast it on themselves.
In the Spellcasting section of the PHB, under "Targeting Yourself", it says:
If a spell targets a creature of your choice, you can choose yourself, unless the creature must be hostile or specifically a creature other than you. If you are in the area of effect of a spell you cast, you can target yourself.
The spell doesn't specify anything about restrictions on the target so yes. You can cast this spell and many other Touch spells on yourself.