I think my sister really hates me am i screwed?

well basically i was helping my 18 year old sister tidy the kitchen and i picked up a spoon to wash it , but when i turned around we collided and she got the contents of the spoon on her dress, she had a massive go at me and is really really angry with me....am i screwed lol? i was thinking of cleaning it myself, taking it to the drycleaners or if they dont work buy her a new dress (the same 1) even no it is really expensive. by the way im 15.