Chocolate Stout Issues with Taste...Infection?

So, just finished a chocolate stout that I hit with 8oz of cocoa nibs in the secondary and hit it with a shot (or big squeeze) of Hershey's chocolate syrup from the bottle. I covered the secondary and let it do its thing for a week or two and when I uncovered the beer in the carboy had a white type gunk floating on top. Looked like small white platelets. Some in my local club thought it could be fat from the chocolate? Anyway the beer had an off smell and bad taste when bottling and I was hoping that once bottled the smell would subside and taste would improve. Tried a bottle last night after 7 days in the bottle and the taste is not great. Awful sour bitter type taste at first. The chocolate stays on the pallet after the bad taste goes away. That's the only positive right now. My question is do you think I have any hope of the bad taste mellowing out in the bottle or due to a possible infection do you think it will ever get any better? Did not sanitize the nibs first which I have read could have been a problem though I have done that before with no issue. Also thinking could have been the chocolate Hershey's syrup? I really focus on sanitation with every brew. Never had an infection in six batches so just cant believe I did anything different here. Any thoughts or ideas out there? Been trying to do all the research I can. Any thing you can offer can only help me improve. Thanks.

It would be a number of things. Check the bottles in three weeks. If you have a gusher then it's probable that an acetobacter decided to hop in and have some fun.

I wouldn't have used the syrup. The nibs would have been enough. The syrup might contain enough fermentable sugars to give you a gusher. If you do have a gusher bottle in the next few weeks you are probably hosting a bad tasting flavor.

The worst case scenario is dumping it or turn it into homemade malt vinegar...Malt vinegar with brown sugar, tomato puree and corn starch makes an excellent bbq sauce.

I appreciate the info. Hopefully it wont come to the BBQ sauce option though that is interesting and will keep that in mind for sure. I think I will have to force drink it either way. The wife is not interested in the "dumping it" option

It sounds like an infection to me. If it is then my guess is that it is from the chocolate syrup or the cocoa nibs.

Excessive cocoa would taste bitter not sour. The "green apple" from a young beer isn't as strong as you are describing, and likely wouldn't even be tasted with everything else going on in a young stout.

Did it look like this link:
http://hbd.org/discus/messages/366/35930.html

It could also just be young. I've gotten a slightly sour taste just from roasted grains. As to the comment about gushers from the syrup it sounded like OP used it in secondary and the sugar in it would have fermented out before bottling. Stouts need a good long time to age before the flavors meld and mellow to a nice smoothness. A week isn't long enough to really tell. Good luck. I hope it's just young and not infected