Welcome! My name isXXXXX am a UC Davis graduate, and currently, a Medical Director of a veterinary hospital.
I am sorry to hear about this concern for Cheyenne.
What you are describing is likely consistent with a aural hematoma. This is when the ear flap ruptures a blood vessel, and the ear fills with fluid. Unfortunately, simply draining it often does not solve the problem, and it will continue to accumulate fluid. The links below will help you to understand the condition better, as well as, treatment options. I am including information about ear infections inside the ear canal, since that is the most common explanation of what causes a hematoma to form. Aural HematomaAural Hematoma (excellent link)
Also, Hematoma are also caused by or accompanied by ear infections (otitis externa):Otitis Externa (Ear infection)
Even though your son got no blood out, he may have not fully penetrated the tissue. Do not have him poke again, as that is introducing bacteria inside of the ear flap as well.
Definitely, wish there was a simple remedy, but there is not. Absolutely, well worth veterinary examination to confirm what is going on. Generally, a surgical procedure to relieve the pressue is needed, as well as, some stitching to help keep the ear flat while scar tissue forms to keep it from filling again.
Please let me know if there is anything I did not cover for you. I hope that information has been helpful.
Please remember to select Reply to Expert, if for any reason you need further clarification, have more questions, or were expecting a different type of answer. DO NOT rate yet if have any other questions. My goal is to try and provide you the best answer possible.