Hello, Welcome to Healthcare Magic. I have read your question fully and understand your concerns. The swelling of the lips and nose is likely to be due to his boil as you mentioned. Or does the boil/lesion have a yellowy crust? In that case it is impetigo, which is a common skin infection. The treatment of boil and impetigo is the same-with Flucloxacillin. Active boil which is oozing discharge/pus and Impetigo are both contagious in the sense that if your son touched his lesion on nose with his fingers and then touched his lips with the same finger, the germs will cause infection of the skin. So meticulous hygeine needs to be maintained. The action of flucloxacillin starts anywhere from 36-48 hours after taking the first dose. So, your son was given his antibiotics yesterday. So, hopefully you would start to see some improvement by tomorrow. As he seems to be in pain, he can have some Paracetamol 3-4 times/day (provided he is not allergic to it). If Paracetamol does not settle his pain, he can even have some Ibuprofen (again provided he is not allergic to it, he should take Ibuprofen with food, as it can cause gastritis when taken on empty stomach).I am sorry, I cannot mention the correct dose as I do not know either your son’s weight or age. If by tomorrow you are not seeing any improvement, rather his symptoms are worsening, or he is developing any new symptoms like fever or vomiting or rash, I would advise you to see his doctor straightaway. I hope this answer has helped you. Thank you Regards Dr Sunita Sayammagaru