Skin around ankles, hip and face swollen

I was sleeping and midnight like around 2am, i got a feeling of irritation and woke up, i saw that just beneath my hip, i had a swelling of like 4-5 cm, it was much bigger than a mosquito bump, same swelling was on my lower tricep, there was so much irritation there, i was very confused as i never had such big swellings like that just pop up midnight. Then smaller swelling like bump came on side of my one eye, and on neck too. I sleep with just wearing vest and underwear. I thought a bug bite me but nothing was there in my room, not even mosquito. But i am worried as i never faced so big bumps midnight and it was at random places on my body too. Can it be any skin allergy which can cause swelling like that, if so please do tell. And what should i do as it has been more than 5hrs now and i still feel irritation and a little bit of swelling is still there, like 40%. Please do tell thanks.