Hemarthrosis is the medical term for bleeding in a joint. When you have pain and swelling in a single joint (monoarticular), hemarthrosis is a common cause. It is a cause for concern not only because of the pain, but because prolonged blood exposure can damage the cartilage.
Injury to the peripheral nerve (nerves outside of the brain and spinal cord) may result from blunt force, fractures, crush injuries, stretch, penetrating or cut injuries. The nerves of the upper limb are the most commonly injured. The healing process from nerve injury can take from a few weeks to a few months.
Answer: Yes, serious nerve damage can occur with sciatica. The pain from sciatica is the result of very real damage to your sciatic nerve. Usually, this damage is only minor and will heal once the pinched nerve is relieved. In all probability it will not result in permanent nerve damage, but the possibility does exist.