My 90 year old dad had a sudden and severe onset of pain in his left thumb last night. In the flesh part there were two areas of blue. One of the areas of blue had a small hard lump. The lump and blue have now gone ( nearly 24 hours later) but the pain is still very severe. He is on warfarin and had his last INR reading 3 days ago and it was 2. The pain is now constant . He has no other symptoms.