Hello, Welcome to Healthcare magic.y I have read your question completely and understand your concerns. The facial blister on your temple could be due to infection from an organism called Staphylococcus present on your skin. Normally your immune system is so strong that you could have eased off that infection. But if there was a small break in the skin the organism could have entered the skin and caused to form the blister. Depending on the severity of the blister ( whether it is just red and angry looking or filled with pus, whether it is a small blister or big one, and whether you have fever/nausea/vomiting or not) you could either try a local cream or oral antibiotics. The cream is Fusidic acid 2% twice a day for 1 week applied on the blister. Antibiotics normally given here is Flucloxacillin 250-500 mg four times a day for a week ( provided you are not allergic to penicillin). This is a prescription only medication, hence you need to see your doctor for this. Lymph nodes normally swell up in the region of local infection. Lymph nodes are store houses of defence cells that fight infection. Once infection settles the lymph node swelling also settles. Is the lymph node is persistently swollen even after 3 weeks, see your doctor. Cold sores also occur due to low immunity. You could Aciclovir cream 5% 5 times a day for 1 week over the sores. I hope this answer has helped you. Thank you Regards Dr Sunita Sayammagaru