Your veterinarian must remove the lump, have it tested and then get back to you with the test results. Just removing the lump requires anesthesia and time handling the surgery. The time it takes depends on the location and size of the lump. This can cost upwards of $300 to $400 in cats and $400 to $500 in dogs.
Many cases of poison oak rashes lasted for 2 to 3 weeks depending on the gravity of the situation. The time it takes for the rashes to heal varies on the exposure of skin to the oil and any possible complications. If the rashes are more severe, then its healing period is expected to take longer. Such cases may last longer than 3 weeks. However, this healing period does not mean 2 or 3 weeks of insane itching.
And even if you don't recall touching the leaves of poison ivy, oak, or sumac, you may have unwittingly come in contact with their roots or stems. Urushiol quickly penetrates the skin, often leaving red lines that show where you brushed against the plant. Symptoms appear 24 to 72 hours after exposure.