Problem using 'Millis' to control on time of two led's

This is just two steps of a test run, eventually there will be more steps. When the button is pressed briefly, led 3 lights for 3 seconds, if the button is pressed for longer the led 4 comes on and the led 3 goes off after 3 seconds. What should then happen is the led 4 goes off after 3 seconds, but it just stays on. Can you see what I am doing wrong?

// Variables constant
const int buttonPin =2;    // button on pin 2 with 10k res to ground
const int led3Pin = 3;      // led on pin 3 via 220 res
const int led4Pin =  4;     // led on pin 4 via 220 res
long interval = 3000L;     // interval 3 seconds

// Variables will change:
int buttonState = 0;
int timeVariable = 0;             // not used yet
long previousMillis = 0;        // will store last time LED was updated

void setup() {
 pinMode (buttonPin, INPUT);
 pinMode(led3Pin, OUTPUT); 
 pinMode(led4Pin, OUTPUT);     
}

void loop()
{
buttonState = digitalRead(buttonPin);  // first led
if (buttonState == HIGH) {
++timeVariable;    // not used yet  
digitalWrite(led3Pin, HIGH);
}
else {
}
{  unsigned long currentMillis = millis();
   if(currentMillis - previousMillis > interval) {
   previousMillis = currentMillis;   
   digitalWrite(led3Pin, LOW);


buttonState = digitalRead(buttonPin);  // second led
if (buttonState == HIGH) {
++timeVariable;  // not used yet    
digitalWrite(led4Pin, HIGH);
}
else {
}
{  unsigned long currentMillis = millis();
   if(currentMillis - previousMillis > interval) {
   previousMillis = currentMillis;   
  digitalWrite(led4Pin, LOW);

  }
}
}
}
}

Use CTRL-T on your code, check the code in the { }s. The two else { } sections do not do anything. Check your logic flow. It is hard to follow as formatted and with what look like extraneous }s at the end.