posession of defective coffee lids

Given the fact that you (fortunately) have no meaningful damages beyond the cost of the product itself, you might be best off demanding that the retailer or manufacturer replace the product and fully reporting the defects in writing to the U.S. Consumer Products Safety Commission.

You can always sue the retailer and perhaps the manufacturer in small claims court, if that make sense.

If you have visions of becoming rich on a lawsuit, forget about it. No damages, no injury does not make you a good representative plaintiff in a class action, and absent serious injury it's not a really good class action case. Do yourself and the public a favor and report it to the Consumer Products Safety Commission and maybe it can help others from being injured.

If you didn't get medical care for your burns, it probably means you won't be able to get very much in damages.

You haven't said what it is about the product that was defective.  That can be hard to prove, sometimes, and in serious cases of this sort both sides will have hired expert witnesses.  To win, you usually have to prove that the product was not just "defective," but unreasonably dangerous.  This gets into questions like the "state of the art" for design of that product.  You also have to show that the product was dangerous when used properly.  For a coffee cup lid, you might need to have the cup as well as the lid, to show that you were using the right size lid for the cup.  The manufacturer can defend the case in a number of ways, sometimes by saying that the product was fine when they sold it, but it was damaged by someone else between them and you.