looks like you may not have swabbed enough.
Cellulitis is a mistaken diagnosis. Cellulitis travels in the skin. Sounds like the problem stems intramuscularly
or... another explaination, You could have knicked a blood vessel, opening up a hematoma deep in your muscle.
This is one explaination I never included in my injection pain sticky and I should probably edit it in.
What happens is the vessel doesn't stop bleeding and slowly fills the cavity where the oil was injected, creating a sterile abcess. The swelling causes pain, and changes in range of motion...
The only quick fix is to find the pocket and drain it, then apply sufficient pressure once the cavity is emptied for a good 15 minutes, so that hemostasis is achieved and the cavity will not just refil with new blood.
In that area, you may need an ultrasound to find the cavity. If you are brave, and remember where you injected, use a large gauge needle and have some fun!
Remember sterility and cleanliness is a priority... the last thing you want to do is introduce anything foreign to the site... Imagine if you had some MRSA residing on your skin! so unless you have some medical training, have the neccessary tools and feel confident doing this yourself... its probably not a good idea to proceed.