Comparing two ints and using the diffrence for a calculation

i have set a personal socre to a player in the game that i am making. i want to update this score if the player wins, but the amount it raises or drops is depending on the diffrence in personal score.

public int editScore(int personalScore){

if(endOfGame().getResult().equals("win")){

now i want to get both players their personal score and compare them to determine how much points will be asigned

        if(this.getPersonalScore.compareTo(partner.getPersonalScore))

how will i make this work? i will need a return of the diffrence between the two.