Had mastoidectomy on Monday is swelling normal? Drainage is pretty much clear. I'm on antibiotics.

Swelling. Assuming the swelling is in the area of your surgery… Yes some swelling is to be expected after surgery. You should have a follow up appointment (post op) with your surgeon. He/she would be happy to answer your questions and would like to know your progress or if you have any questions, they know your case and situation the best and should be informed. Do not be afraid to call your surgeon.
Normal swelling. Some swelling is normal after most operations. If it seems excessive, or you think it's "not right", then call your surgeon to have a look. Ask if you can send them a photo of the area electronically, recognizing that may not be a fully secure way of transmitting that information. Hope this helps!