<s>[INST] My 8 year old son complained of pain in his armpit last night. He lifted arm to reveal a golf ball size lump. He has been stung by a bee recently, and also has had a cold, low grade fever. He is eating and drinking, but complaining of fatigue. What should I do? [/INST] I went through your explanation and realize first you also need to see is this pain is recent start up after be bite, or it was there before also.  If it is after being bite don't worry it will get over, but he needs some anti-inflammatory with painkiller as well antibiotic tablets also for this visit your doctor.  And if pain in arm pit is present from long time before the bee bite then you need to check the lump with doctor what kind of lump is that.  May need to go for excision as well biopsy of it to plan further.  And here again a course of anti-biotic as well anti-inflammatory and painkiller will be given.  So in both the cases you need to visit your physician first, and he will guide you further after physical examination.  Hope you got your answer. Take care </s>