Intense pain from the pressure of the contained hematoma can be relieved via aseptic trephination. The nail bed and overlying hematoma are sterile spaces so any attempt should be preceded by sterilization with povidone iodine or chlorhexidine (care should be taken with isopropyl alcohol and high temperatures to avoid a fire).
The quickest and simplest way to trephinate the nail is to use a cautery device. There are other techniques described, such as using a hot paper clip, spinning a needle, or elevating the nail with a small needle. (references) However, a cautery device is recommended for simplicity and efficacy. No anesthesia is required. The device should be gently touched to the center of the nail discoloration until it is just through the nail. Blood will leak out of the hole. The cautery should then be quickly withdrawn so not to penetrate the underlying skin. Blood can be expressed to decompress the nail if it does not ooze out spontaneously. Patients will often have apprehension about the use of heat and may have brief discomfort immediately after nail penetration. Successful trephination will often provide immediate relief. Reassuring patients of this will help them through the procedure.
If there is clinical concern for fracture the digit should be x-rayed however the presence of a fracture is not a contraindication for trephination.