11 Red Wasp stings

My husband got stung by a red waspts 2 days ago behind his left ear/neck 3 times, his right upper arm/bicept at least 6 times & his chin twice.  He is allergic to them but as he's gotten older (he's 42) he seems to be growing out of it.  My question is....on the right arm the red swollen where area where they stung him covers more than half his arm, looks like his arm muscle is alot bigger than normal.  He does have a rash, his muscle feels tight, pain in every area stung & at the bend of the right arm it feels like it wants to lock up.  What do we need to do? He has taken bendryl.
Thanks, Meeler

[Paderla Anitha, DNB]

Hello and hope you are doing well.

Looks like the rash and blisters have resulted in an infection. If left untreated it could result in an abscess. So, please consult your doctor who will examine him and may ask for a few blood tests. Ha may also prescribe antibiotics and anti inflammatory medications to tackle the infection and pain.

Hope this helped and do keep us posted.