Hello and hope you are doing well.
It could be an allergic reaction, if this occurs repeatedly with using the condom. The other causes could be due to a fungal infection, atopic dermatitis, contact dermatitis, balanitis and sexually transmitted diseases. Usually there is itching and some amount of inflammation with these conditions. You may need to consult your primary care physician who will examine you and may ask for blood tests to initiate appropriate therapy. In the meantime try to avoid using condoms and see if the inflammation subsides.
Hope this helped and do keep us posted.