 [ Symptoms ] should the boil form a yellowish film after drainage [ Disease ] that yellowish film you see probably is part of the healing process as the body heals a wound it frequently produces an overabundance of proteins these proteins often look exactly like your description a yellowish film this film often is described as thick sticky or gunky as long as the area of the boil does not become extremely painful red or hot and as long as you do not start running a fever the healing process is likely proceeding normally if you experience any of the above symptoms you should contact your primary care provider you can gently cleanse the area with lukewarm water and mild soap you do not need to scrub off the yellowish film hope this helps