Hey there @luenbore,
Yes, you can still replace the battery, but I would exercise caution when doing so. I would highly recommend taking a look at iFixit's article on [[What to do with a swollen battery|What to do with a swollen battery]], and using the advice from the [[What to do with a swollen battery#Section_How_to_safely_remove_a_swollen_battery|How to safely remove a swollen battery section]] in conjunction with the [guide|60358|Battery Replacement guide]. I would especially exercise caution around steps 52 through 59, and have a prepared fireproof container, such as a sealed metal can, metal bucket of sand, or equivalent.