How do you remove blue and purple hair dye from light blonde hair?

Okay so I dyed my side swept bangs purple about a week or two ago then i went simming and it like turned pinkish blonidish grayish purple. So then I dyed it blue and its still has purplein it and its pretty but I went swimming today and it started to wash out :(( So I decided I wanna go blonde again... It was the SPLAT temporary hair dye.. PLEASE HELP ME OR ELSE ILL CRY!!!! :'( Okay thank yew :X