For extra experience, the player can go behind the curtain in Dr. Razlo's house to find a man laying on a futon, then go into the player's inventory, equip the antidote and "use it on the man", who is called Jarvis. Jarvis is the brother of Seth (The captain of Shady Sands' guard). Jarvis was poisoned by a Radscorpion, and in return for healing him you'll receive 400 XP.
If the Vault Dweller is low on health after fighting the radscorpions, do not waste their stimpaks in order to heal. Instead, when the Vault Dweller talks to Dr. Razlo (before giving him the tail) ask him to heal you, he'll give you a price for his services. Refuse to pay for his medical services, you should be able to offer him a radscorpion tail instead of money.
By doing this, Dr. Razlo will heal you to full health for free, while also giving you the antidote and 250 XP. He'll even do this at night.