48 hours ago i had my bottom left molar extracted , it was double rooted , and ive noticed a mostly white but slightly yellow layer across the top of the extraction site. is this normal or should i be worried ?

Normal: Post surgical care is part of your surgical treatment. Concerns should be directed to the General Dentist or specialist Oral Surgeon that removed your tooth. However what you describe sounds to be normal. Pain should be deminishing, you should no longer have bad taste or smell. Your Dentist knows you best. Ask his/her advice.

Post extraction: There will be tissue forming as part of the healing process. Make sure you are following the post op instructions given by the extracting dentist. The best newer to your question can be gotten by contacting the dentist who did the extraction. They know your mouth and the nature of the extraction and will be able to let you know what is going on. Call today.