Welcome to just answer.
Well there is possibility of perianal infection in the form of boils,Abscess and Perianal Dermatoses, which include a number of conditions including benign conditions like dermatitis to more severe and advanced malignancies.In my opinion , he needs to have a detailed clinical examination to exactly find out the cause for his symptoms.Some tests, including blood tests, and imaging studies may also be required.Its important to note that an early diagnosis directs an early treatment, and therefore prevents any possible complications.While awaiting consultation, he should maintain a good hygiene of the area, and should not scratch.In case of pain, he can take tylenol.There is nothing much to offer as self management, and he needs help of a doctor.
I hope i have been helpful.
How far is this from his anus?
Is the skin red?
Is there a blueish tinge to the lump?
Is it painful?
Has he a fever ?
No fever, no bluish tinge it is like a lump of skin and is red and he says it is painful. It is on the very edge of his anus.
This certainly sounds like a peri-anal abscess although it may , less likely , be a thrombosed external hemorrhoid.
The usual treatment would be antibiotics +/- surgical drainage.
If a visit to the Dr is not an option then all he can really do is take pain relief and hope that it bursts soon by itself.
If he has a PCP it may be worth giving him/her a call to see if they would be prepared to leave him a prescription for an antibiotic.
Please get back to me if you would like to discuss this some more.