I'm sorry there was a delay in getting to your question, sometimes they slip off the 'waiting room' (front page) and get missed.
How is your hen today? Have you noticed any changes in droppings? How about coordination or how she holds her head/neck?
Look at her eyes: Are they normal colored irises with regular shaped pupils that react to light. You can test this by shading her eyes with one hand and noting whether the pupils dilate and then contract when you remove your hand and let full light hit them.
Is this growth yellowish? Does it feel solid or moveable and fatty?
Is the skin discoloration only in the area of the growth or overall?