I started taking an antibiotic on Sunday to fight a skin infection on my face. I weigh myself once a week on Fridays and I am up 4 lbs. My eating patterns haven't changed.

The only thing different in my routine I will be done with this after this weekend. Is there anything I can do change the course or will I just have to wait it out and if so how long will this affect my weight?

Antibiotics can mess with weight loss, especially if you have any yeast issues.
Stick to your plan and the weight will come back off, in it's own time.

Heck yes! It's why they give cattle antibiotics. Makes 'em gain weight like mad so they can slaughter them sooner.

I would try adding probiotics, yogurt, and/or fermented foods to your routine. This will help rebuild the gut flora antibiotics destroy.

Thank you all for the all the advice and comments. For yogurt any special kind and how much and how often?

Like others have said I would think the med can mess with you, but for me I can be up 4lbs on the scale one week and back down 3 the next week, up 2, down 4..... I'm like a roller coaster sometimes. Eating may never change, no rhyme or readin. Just gotta ride it out! Looks like you're having some good progress so far though. Keep it up!