Emergency Situation

I need some immediate guidance. Today I told my K / H that the way is clear for me to slip my penis out of its holder. We agreed on swapping in the tiniest ring available. Perhaps we rushed it a bit. Right after putting on the new ring, I got fully erect. The cage fits snugly, holding both my shaft and testicles quite firmly. Pain levels started climbing quickly. So I made a swift call to take everything off. Things are settling down slightly now, but my BF is getting anxious. Could someone help reassure him? We’re looking for some grounded advice here. He’s considering taking me to the ER, while I’d rather just lie still and recover.